diff --git a/debug_test.go b/debug_test.go
index 06e2b6ae0c..3569e3f493 100644
--- a/debug_test.go
+++ b/debug_test.go
@@ -83,7 +83,7 @@ func TestTraceDivBy0(t *testing.T) {
 	{
 		_, err := getGroth16Trace(&circuit, &witness)
 		assert.Error(err)
-		assert.Contains(err.Error(), "constraint is not satisfied: [div] 2/(-2 + 2) == <unsolved>")
+		assert.Contains(err.Error(), "constraint #0 is not satisfied: [div] 2/(-2 + 2) == <unsolved>")
 		assert.Contains(err.Error(), "(*divBy0Trace).Define")
 		assert.Contains(err.Error(), "debug_test.go:")
 	}
@@ -91,7 +91,7 @@ func TestTraceDivBy0(t *testing.T) {
 	{
 		_, err := getPlonkTrace(&circuit, &witness)
 		assert.Error(err)
-		assert.Contains(err.Error(), "constraint is not satisfied: [inverse] 1/0 < ∞")
+		assert.Contains(err.Error(), "constraint #1 is not satisfied: [inverse] 1/0 < ∞")
 		assert.Contains(err.Error(), "(*divBy0Trace).Define")
 		assert.Contains(err.Error(), "debug_test.go:")
 	}
@@ -120,7 +120,7 @@ func TestTraceNotEqual(t *testing.T) {
 	{
 		_, err := getGroth16Trace(&circuit, &witness)
 		assert.Error(err)
-		assert.Contains(err.Error(), "constraint is not satisfied: [assertIsEqual] 1 == (24 + 42)")
+		assert.Contains(err.Error(), "constraint #0 is not satisfied: [assertIsEqual] 1 == (24 + 42)")
 		assert.Contains(err.Error(), "(*notEqualTrace).Define")
 		assert.Contains(err.Error(), "debug_test.go:")
 	}
@@ -128,7 +128,7 @@ func TestTraceNotEqual(t *testing.T) {
 	{
 		_, err := getPlonkTrace(&circuit, &witness)
 		assert.Error(err)
-		assert.Contains(err.Error(), "constraint is not satisfied: [assertIsEqual] 1 + -66 == 0")
+		assert.Contains(err.Error(), "constraint #1 is not satisfied: [assertIsEqual] 1 + -66 == 0")
 		assert.Contains(err.Error(), "(*notEqualTrace).Define")
 		assert.Contains(err.Error(), "debug_test.go:")
 	}
@@ -157,7 +157,7 @@ func TestTraceNotBoolean(t *testing.T) {
 	{
 		_, err := getGroth16Trace(&circuit, &witness)
 		assert.Error(err)
-		assert.Contains(err.Error(), "constraint is not satisfied: [assertIsBoolean] (24 + 42) == (0|1)")
+		assert.Contains(err.Error(), "constraint #0 is not satisfied: [assertIsBoolean] (24 + 42) == (0|1)")
 		assert.Contains(err.Error(), "(*notBooleanTrace).Define")
 		assert.Contains(err.Error(), "debug_test.go:")
 	}
@@ -165,7 +165,7 @@ func TestTraceNotBoolean(t *testing.T) {
 	{
 		_, err := getPlonkTrace(&circuit, &witness)
 		assert.Error(err)
-		assert.Contains(err.Error(), "constraint is not satisfied: [assertIsBoolean] 66 == (0|1)")
+		assert.Contains(err.Error(), "constraint #1 is not satisfied: [assertIsBoolean] 66 == (0|1)")
 		assert.Contains(err.Error(), "(*notBooleanTrace).Define")
 		assert.Contains(err.Error(), "debug_test.go:")
 	}
diff --git a/frontend/ccs.go b/frontend/ccs.go
index e867502a3e..d3659cc5c5 100644
--- a/frontend/ccs.go
+++ b/frontend/ccs.go
@@ -41,9 +41,6 @@ type CompiledConstraintSystem interface {
 	CurveID() ecc.ID
 	FrSize() int
 
-	// ToHTML generates a human readable representation of the constraint system
-	ToHTML(w io.Writer) error
-
 	// GetCounters return the collected constraint counters, if any
 	GetCounters() []compiled.Counter
 
diff --git a/internal/backend/bls12-377/cs/r1cs.go b/internal/backend/bls12-377/cs/r1cs.go
index 00fe977d7d..b2c0f0ee04 100644
--- a/internal/backend/bls12-377/cs/r1cs.go
+++ b/internal/backend/bls12-377/cs/r1cs.go
@@ -32,7 +32,6 @@ import (
 	"github.com/consensys/gnark/internal/backend/ioutils"
 
 	"github.com/consensys/gnark-crypto/ecc"
-	"text/template"
 
 	"github.com/consensys/gnark-crypto/ecc/bls12-377/fr"
 
@@ -119,11 +118,11 @@ func (cs *R1CS) Solve(witness, a, b, c []fr.Element, opt backend.ProverConfig) (
 		// ensure a[i] * b[i] == c[i]
 		check.Mul(&a[i], &b[i])
 		if !check.Equal(&c[i]) {
+			errMsg := fmt.Sprintf("%s ⋅ %s != %s", a[i].String(), b[i].String(), c[i].String())
 			if dID, ok := cs.MDebug[i]; ok {
-				debugInfoStr := solution.logValue(cs.DebugInfo[dID])
-				return solution.values, fmt.Errorf("%w: %s", ErrUnsatisfiedConstraint, debugInfoStr)
+				errMsg = solution.logValue(cs.DebugInfo[dID])
 			}
-			return solution.values, ErrUnsatisfiedConstraint
+			return solution.values, fmt.Errorf("constraint #%d is not satisfied: %s", i, errMsg)
 		}
 	}
 
@@ -289,32 +288,10 @@ func (cs *R1CS) solveConstraint(r compiled.R1C, solution *solution) error {
 	return nil
 }
 
-// TODO @gbotrel clean logs and html see https://github.com/ConsenSys/gnark/issues/140
-
-// ToHTML returns an HTML human-readable representation of the constraint system
-func (cs *R1CS) ToHTML(w io.Writer) error {
-	t, err := template.New("cs.html").Funcs(template.FuncMap{
-		"toHTML": toHTML,
-		"add":    add,
-		"sub":    sub,
-	}).Parse(compiled.R1CSTemplate)
-	if err != nil {
-		return err
-	}
-
-	return t.Execute(w, cs)
-}
-
-func add(a, b int) int {
-	return a + b
-}
-
-func sub(a, b int) int {
-	return a - b
-}
-
+// GetConstraints return a list of constraint formatted as L⋅R == O
+// such that [0] -> L, [1] -> R, [2] -> O
 func (cs *R1CS) GetConstraints() [][]string {
-	var r [][]string
+	r := make([][]string, len(cs.Constraints))
 	for _, c := range cs.Constraints {
 		// for each constraint, we build a string representation of it's L, R and O part
 		// if we are worried about perf for large cs, we could do a string builder + csv format.
@@ -350,7 +327,7 @@ func (cs *R1CS) termToString(t compiled.Term, sbb *strings.Builder) {
 		return
 	} else {
 		sbb.WriteString(cs.Coefficients[tID].String())
-		sbb.WriteByte('*')
+		sbb.WriteString("⋅")
 	}
 	vID := t.WireID()
 	visibility := t.VariableVisibility()
@@ -375,59 +352,6 @@ func (cs *R1CS) termToString(t compiled.Term, sbb *strings.Builder) {
 	}
 }
 
-func toHTML(l compiled.Variable, coeffs []fr.Element, MHints map[int]compiled.Hint) string {
-	var sbb strings.Builder
-	for i := 0; i < len(l.LinExp); i++ {
-		termToHTML(l.LinExp[i], &sbb, coeffs, MHints, false)
-		if i+1 < len(l.LinExp) {
-			sbb.WriteString(" + ")
-		}
-	}
-	return sbb.String()
-}
-
-func termToHTML(t compiled.Term, sbb *strings.Builder, coeffs []fr.Element, MHints map[int]compiled.Hint, offset bool) {
-	tID := t.CoeffID()
-	if tID == compiled.CoeffIdOne {
-		// do nothing, just print the variable
-	} else if tID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		sbb.WriteString("<span class=\"coefficient\">-</span>")
-	} else if tID == compiled.CoeffIdZero {
-		sbb.WriteString("<span class=\"coefficient\">0</span>")
-		return
-	} else {
-		sbb.WriteString("<span class=\"coefficient\">")
-		sbb.WriteString(coeffs[tID].String())
-		sbb.WriteString("</span>*")
-	}
-
-	vID := t.WireID()
-	class := ""
-	switch t.VariableVisibility() {
-	case schema.Internal:
-		class = "internal"
-		if _, ok := MHints[vID]; ok {
-			class = "hint"
-		}
-	case schema.Public:
-		class = "public"
-	case schema.Secret:
-		class = "secret"
-	case schema.Virtual:
-		class = "virtual"
-	case schema.Unset:
-		class = "unset"
-	default:
-		panic("not implemented")
-	}
-	if offset {
-		vID++ // for sparse R1CS, we offset to have same variable numbers as in R1CS
-	}
-	sbb.WriteString(fmt.Sprintf("<span class=\"%s\">v%d</span>", class, vID))
-
-}
-
 // GetNbCoefficients return the number of unique coefficients needed in the R1CS
 func (cs *R1CS) GetNbCoefficients() int {
 	return len(cs.Coefficients)
diff --git a/internal/backend/bls12-377/cs/r1cs_sparse.go b/internal/backend/bls12-377/cs/r1cs_sparse.go
index c8b89de4bb..57b0a41588 100644
--- a/internal/backend/bls12-377/cs/r1cs_sparse.go
+++ b/internal/backend/bls12-377/cs/r1cs_sparse.go
@@ -24,7 +24,6 @@ import (
 	"math/big"
 	"os"
 	"strings"
-	"text/template"
 
 	"github.com/consensys/gnark/backend"
 	"github.com/consensys/gnark/backend/witness"
@@ -110,11 +109,11 @@ func (cs *SparseR1CS) Solve(witness []fr.Element, opt backend.ProverConfig) ([]f
 			return solution.values, fmt.Errorf("constraint %d: %w", i, err)
 		}
 		if err := cs.checkConstraint(cs.Constraints[i], &solution); err != nil {
+			errMsg := err.Error()
 			if dID, ok := cs.MDebug[i]; ok {
-				debugInfoStr := solution.logValue(cs.DebugInfo[dID])
-				return solution.values, fmt.Errorf("%w: %s", ErrUnsatisfiedConstraint, debugInfoStr)
+				errMsg = solution.logValue(cs.DebugInfo[dID])
 			}
-			return solution.values, ErrUnsatisfiedConstraint
+			return solution.values, fmt.Errorf("constraint #%d is not satisfied: %s", i, errMsg)
 		}
 	}
 
@@ -255,37 +254,81 @@ func (cs *SparseR1CS) IsSolved(witness *witness.Witness, opts ...backend.ProverO
 	return err
 }
 
+// GetConstraints return a list of constraint formatted as in the paper
+// https://eprint.iacr.org/2019/953.pdf section 6 such that
+// qL⋅xa + qR⋅xb + qO⋅xc + qM⋅(xaxb) + qC == 0
+// each constraint is thus decomposed in [5]string with
+// 		[0] = qL⋅xa
+//		[1] = qR⋅xb
+//		[2] = qO⋅xc
+//		[3] = qM⋅(xaxb)
+//		[4] = qC
 func (cs *SparseR1CS) GetConstraints() [][]string {
-	var r [][]string
+	r := make([][]string, 0, len(cs.Constraints))
 	for _, c := range cs.Constraints {
-		// if we are worried about perf for large cs, we could do a string builder + csv format.
-		var line [6]string
-		line[0] = cs.termToString(c.L)
-		line[1] = cs.termToString(c.R)
-		line[2] = cs.termToString(c.M[0])
-		line[3] = cs.termToString(c.M[1])
-		line[4] = cs.termToString(c.O)
-		line[5] = cs.Coefficients[c.K].String()
-		r = append(r, line[:])
+		fc := cs.formatConstraint(c)
+		r = append(r, fc[:])
 	}
 	return r
 }
 
-func (cs *SparseR1CS) termToString(t compiled.Term) string {
+// r[0] = qL⋅xa
+// r[1] = qR⋅xb
+// r[2] = qO⋅xc
+// r[3] = qM⋅(xaxb)
+// r[4] = qC
+func (cs *SparseR1CS) formatConstraint(c compiled.SparseR1C) (r [5]string) {
+	isZeroM := (c.M[0].CoeffID() == compiled.CoeffIdZero) && (c.M[1].CoeffID() == compiled.CoeffIdZero)
+
 	var sbb strings.Builder
-	tID := t.CoeffID()
-	if tID == compiled.CoeffIdOne {
-		// do nothing, just print the variable
-	} else if tID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		sbb.WriteByte('-')
-	} else if tID == compiled.CoeffIdZero {
-		sbb.WriteByte('0')
-		return sbb.String()
+	cs.termToString(c.L, &sbb, false)
+	r[0] = sbb.String()
+
+	sbb.Reset()
+	cs.termToString(c.R, &sbb, false)
+	r[1] = sbb.String()
+
+	sbb.Reset()
+	cs.termToString(c.O, &sbb, false)
+	r[2] = sbb.String()
+
+	if isZeroM {
+		r[3] = "0"
 	} else {
-		sbb.WriteString(cs.Coefficients[tID].String())
-		sbb.WriteByte('*')
+		sbb.Reset()
+		sbb.WriteString(cs.Coefficients[c.M[0].CoeffID()].String())
+		sbb.WriteString("⋅")
+		sbb.WriteByte('(')
+		cs.termToString(c.M[0], &sbb, true)
+		sbb.WriteString(" × ")
+		cs.termToString(c.M[1], &sbb, true)
+		sbb.WriteByte(')')
+		r[3] = sbb.String()
+	}
+
+	r[4] = cs.Coefficients[c.K].String()
+
+	return
+}
+
+func (cs *SparseR1CS) termToString(t compiled.Term, sbb *strings.Builder, vOnly bool) {
+	if !vOnly {
+		tID := t.CoeffID()
+		if tID == compiled.CoeffIdOne {
+			// do nothing, just print the variable
+			sbb.WriteString("1")
+		} else if tID == compiled.CoeffIdMinusOne {
+			// print neg sign
+			sbb.WriteString("-1")
+		} else if tID == compiled.CoeffIdZero {
+			sbb.WriteByte('0')
+			return
+		} else {
+			sbb.WriteString(cs.Coefficients[tID].String())
+		}
+		sbb.WriteString("⋅")
 	}
+
 	vID := t.WireID()
 	visibility := t.VariableVisibility()
 
@@ -303,7 +346,6 @@ func (cs *SparseR1CS) termToString(t compiled.Term) string {
 	default:
 		sbb.WriteString("<?>")
 	}
-	return sbb.String()
 }
 
 // checkConstraint verifies that the constraint holds
@@ -318,12 +360,12 @@ func (cs *SparseR1CS) checkConstraint(c compiled.SparseR1C, solution *solution)
 	var t fr.Element
 	t.Mul(&m0, &m1).Add(&t, &l).Add(&t, &r).Add(&t, &o).Add(&t, &cs.Coefficients[c.K])
 	if !t.IsZero() {
-		return fmt.Errorf("%w\n%s + %s + (%s * %s) + %s + %s != 0", ErrUnsatisfiedConstraint,
+		return fmt.Errorf("qL⋅xa + qR⋅xb + qO⋅xc + qM⋅(xaxb) + qC != 0 → %s + %s + %s + (%s × %s) + %s != 0",
 			l.String(),
 			r.String(),
+			o.String(),
 			m0.String(),
 			m1.String(),
-			o.String(),
 			cs.Coefficients[c.K].String(),
 		)
 	}
@@ -331,39 +373,6 @@ func (cs *SparseR1CS) checkConstraint(c compiled.SparseR1C, solution *solution)
 
 }
 
-// ToHTML returns an HTML human-readable representation of the constraint system
-func (cs *SparseR1CS) ToHTML(w io.Writer) error {
-	t, err := template.New("scs.html").Funcs(template.FuncMap{
-		"toHTML":      toHTMLTerm,
-		"toHTMLCoeff": toHTMLCoeff,
-		"add":         add,
-		"sub":         sub,
-	}).Parse(compiled.SparseR1CSTemplate)
-	if err != nil {
-		return err
-	}
-
-	return t.Execute(w, cs)
-}
-
-func toHTMLTerm(t compiled.Term, coeffs []fr.Element, MHints map[int]compiled.Hint) string {
-	var sbb strings.Builder
-	termToHTML(t, &sbb, coeffs, MHints, true)
-	return sbb.String()
-}
-
-func toHTMLCoeff(cID int, coeffs []fr.Element) string {
-	if cID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		return "<span class=\"coefficient\">-1</span>"
-	}
-	var sbb strings.Builder
-	sbb.WriteString("<span class=\"coefficient\">")
-	sbb.WriteString(coeffs[cID].String())
-	sbb.WriteString("</span>")
-	return sbb.String()
-}
-
 // FrSize return fr.Limbs * 8, size in byte of a fr element
 func (cs *SparseR1CS) FrSize() int {
 	return fr.Limbs * 8
diff --git a/internal/backend/bls12-377/cs/solution.go b/internal/backend/bls12-377/cs/solution.go
index cdef436358..99ddb85aaf 100644
--- a/internal/backend/bls12-377/cs/solution.go
+++ b/internal/backend/bls12-377/cs/solution.go
@@ -33,9 +33,6 @@ import (
 	curve "github.com/consensys/gnark-crypto/ecc/bls12-377"
 )
 
-// ErrUnsatisfiedConstraint can be generated when solving a R1CS
-var ErrUnsatisfiedConstraint = errors.New("constraint is not satisfied")
-
 // solution represents elements needed to compute
 // a solution to a R1CS or SparseR1CS
 type solution struct {
diff --git a/internal/backend/bls12-381/cs/r1cs.go b/internal/backend/bls12-381/cs/r1cs.go
index 66df1f795f..fbecb56a02 100644
--- a/internal/backend/bls12-381/cs/r1cs.go
+++ b/internal/backend/bls12-381/cs/r1cs.go
@@ -32,7 +32,6 @@ import (
 	"github.com/consensys/gnark/internal/backend/ioutils"
 
 	"github.com/consensys/gnark-crypto/ecc"
-	"text/template"
 
 	"github.com/consensys/gnark-crypto/ecc/bls12-381/fr"
 
@@ -119,11 +118,11 @@ func (cs *R1CS) Solve(witness, a, b, c []fr.Element, opt backend.ProverConfig) (
 		// ensure a[i] * b[i] == c[i]
 		check.Mul(&a[i], &b[i])
 		if !check.Equal(&c[i]) {
+			errMsg := fmt.Sprintf("%s ⋅ %s != %s", a[i].String(), b[i].String(), c[i].String())
 			if dID, ok := cs.MDebug[i]; ok {
-				debugInfoStr := solution.logValue(cs.DebugInfo[dID])
-				return solution.values, fmt.Errorf("%w: %s", ErrUnsatisfiedConstraint, debugInfoStr)
+				errMsg = solution.logValue(cs.DebugInfo[dID])
 			}
-			return solution.values, ErrUnsatisfiedConstraint
+			return solution.values, fmt.Errorf("constraint #%d is not satisfied: %s", i, errMsg)
 		}
 	}
 
@@ -289,32 +288,10 @@ func (cs *R1CS) solveConstraint(r compiled.R1C, solution *solution) error {
 	return nil
 }
 
-// TODO @gbotrel clean logs and html see https://github.com/ConsenSys/gnark/issues/140
-
-// ToHTML returns an HTML human-readable representation of the constraint system
-func (cs *R1CS) ToHTML(w io.Writer) error {
-	t, err := template.New("cs.html").Funcs(template.FuncMap{
-		"toHTML": toHTML,
-		"add":    add,
-		"sub":    sub,
-	}).Parse(compiled.R1CSTemplate)
-	if err != nil {
-		return err
-	}
-
-	return t.Execute(w, cs)
-}
-
-func add(a, b int) int {
-	return a + b
-}
-
-func sub(a, b int) int {
-	return a - b
-}
-
+// GetConstraints return a list of constraint formatted as L⋅R == O
+// such that [0] -> L, [1] -> R, [2] -> O
 func (cs *R1CS) GetConstraints() [][]string {
-	var r [][]string
+	r := make([][]string, len(cs.Constraints))
 	for _, c := range cs.Constraints {
 		// for each constraint, we build a string representation of it's L, R and O part
 		// if we are worried about perf for large cs, we could do a string builder + csv format.
@@ -350,7 +327,7 @@ func (cs *R1CS) termToString(t compiled.Term, sbb *strings.Builder) {
 		return
 	} else {
 		sbb.WriteString(cs.Coefficients[tID].String())
-		sbb.WriteByte('*')
+		sbb.WriteString("⋅")
 	}
 	vID := t.WireID()
 	visibility := t.VariableVisibility()
@@ -375,59 +352,6 @@ func (cs *R1CS) termToString(t compiled.Term, sbb *strings.Builder) {
 	}
 }
 
-func toHTML(l compiled.Variable, coeffs []fr.Element, MHints map[int]compiled.Hint) string {
-	var sbb strings.Builder
-	for i := 0; i < len(l.LinExp); i++ {
-		termToHTML(l.LinExp[i], &sbb, coeffs, MHints, false)
-		if i+1 < len(l.LinExp) {
-			sbb.WriteString(" + ")
-		}
-	}
-	return sbb.String()
-}
-
-func termToHTML(t compiled.Term, sbb *strings.Builder, coeffs []fr.Element, MHints map[int]compiled.Hint, offset bool) {
-	tID := t.CoeffID()
-	if tID == compiled.CoeffIdOne {
-		// do nothing, just print the variable
-	} else if tID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		sbb.WriteString("<span class=\"coefficient\">-</span>")
-	} else if tID == compiled.CoeffIdZero {
-		sbb.WriteString("<span class=\"coefficient\">0</span>")
-		return
-	} else {
-		sbb.WriteString("<span class=\"coefficient\">")
-		sbb.WriteString(coeffs[tID].String())
-		sbb.WriteString("</span>*")
-	}
-
-	vID := t.WireID()
-	class := ""
-	switch t.VariableVisibility() {
-	case schema.Internal:
-		class = "internal"
-		if _, ok := MHints[vID]; ok {
-			class = "hint"
-		}
-	case schema.Public:
-		class = "public"
-	case schema.Secret:
-		class = "secret"
-	case schema.Virtual:
-		class = "virtual"
-	case schema.Unset:
-		class = "unset"
-	default:
-		panic("not implemented")
-	}
-	if offset {
-		vID++ // for sparse R1CS, we offset to have same variable numbers as in R1CS
-	}
-	sbb.WriteString(fmt.Sprintf("<span class=\"%s\">v%d</span>", class, vID))
-
-}
-
 // GetNbCoefficients return the number of unique coefficients needed in the R1CS
 func (cs *R1CS) GetNbCoefficients() int {
 	return len(cs.Coefficients)
diff --git a/internal/backend/bls12-381/cs/r1cs_sparse.go b/internal/backend/bls12-381/cs/r1cs_sparse.go
index b528dc3a21..850c85b0fb 100644
--- a/internal/backend/bls12-381/cs/r1cs_sparse.go
+++ b/internal/backend/bls12-381/cs/r1cs_sparse.go
@@ -24,7 +24,6 @@ import (
 	"math/big"
 	"os"
 	"strings"
-	"text/template"
 
 	"github.com/consensys/gnark/backend"
 	"github.com/consensys/gnark/backend/witness"
@@ -110,11 +109,11 @@ func (cs *SparseR1CS) Solve(witness []fr.Element, opt backend.ProverConfig) ([]f
 			return solution.values, fmt.Errorf("constraint %d: %w", i, err)
 		}
 		if err := cs.checkConstraint(cs.Constraints[i], &solution); err != nil {
+			errMsg := err.Error()
 			if dID, ok := cs.MDebug[i]; ok {
-				debugInfoStr := solution.logValue(cs.DebugInfo[dID])
-				return solution.values, fmt.Errorf("%w: %s", ErrUnsatisfiedConstraint, debugInfoStr)
+				errMsg = solution.logValue(cs.DebugInfo[dID])
 			}
-			return solution.values, ErrUnsatisfiedConstraint
+			return solution.values, fmt.Errorf("constraint #%d is not satisfied: %s", i, errMsg)
 		}
 	}
 
@@ -255,37 +254,81 @@ func (cs *SparseR1CS) IsSolved(witness *witness.Witness, opts ...backend.ProverO
 	return err
 }
 
+// GetConstraints return a list of constraint formatted as in the paper
+// https://eprint.iacr.org/2019/953.pdf section 6 such that
+// qL⋅xa + qR⋅xb + qO⋅xc + qM⋅(xaxb) + qC == 0
+// each constraint is thus decomposed in [5]string with
+// 		[0] = qL⋅xa
+//		[1] = qR⋅xb
+//		[2] = qO⋅xc
+//		[3] = qM⋅(xaxb)
+//		[4] = qC
 func (cs *SparseR1CS) GetConstraints() [][]string {
-	var r [][]string
+	r := make([][]string, 0, len(cs.Constraints))
 	for _, c := range cs.Constraints {
-		// if we are worried about perf for large cs, we could do a string builder + csv format.
-		var line [6]string
-		line[0] = cs.termToString(c.L)
-		line[1] = cs.termToString(c.R)
-		line[2] = cs.termToString(c.M[0])
-		line[3] = cs.termToString(c.M[1])
-		line[4] = cs.termToString(c.O)
-		line[5] = cs.Coefficients[c.K].String()
-		r = append(r, line[:])
+		fc := cs.formatConstraint(c)
+		r = append(r, fc[:])
 	}
 	return r
 }
 
-func (cs *SparseR1CS) termToString(t compiled.Term) string {
+// r[0] = qL⋅xa
+// r[1] = qR⋅xb
+// r[2] = qO⋅xc
+// r[3] = qM⋅(xaxb)
+// r[4] = qC
+func (cs *SparseR1CS) formatConstraint(c compiled.SparseR1C) (r [5]string) {
+	isZeroM := (c.M[0].CoeffID() == compiled.CoeffIdZero) && (c.M[1].CoeffID() == compiled.CoeffIdZero)
+
 	var sbb strings.Builder
-	tID := t.CoeffID()
-	if tID == compiled.CoeffIdOne {
-		// do nothing, just print the variable
-	} else if tID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		sbb.WriteByte('-')
-	} else if tID == compiled.CoeffIdZero {
-		sbb.WriteByte('0')
-		return sbb.String()
+	cs.termToString(c.L, &sbb, false)
+	r[0] = sbb.String()
+
+	sbb.Reset()
+	cs.termToString(c.R, &sbb, false)
+	r[1] = sbb.String()
+
+	sbb.Reset()
+	cs.termToString(c.O, &sbb, false)
+	r[2] = sbb.String()
+
+	if isZeroM {
+		r[3] = "0"
 	} else {
-		sbb.WriteString(cs.Coefficients[tID].String())
-		sbb.WriteByte('*')
+		sbb.Reset()
+		sbb.WriteString(cs.Coefficients[c.M[0].CoeffID()].String())
+		sbb.WriteString("⋅")
+		sbb.WriteByte('(')
+		cs.termToString(c.M[0], &sbb, true)
+		sbb.WriteString(" × ")
+		cs.termToString(c.M[1], &sbb, true)
+		sbb.WriteByte(')')
+		r[3] = sbb.String()
+	}
+
+	r[4] = cs.Coefficients[c.K].String()
+
+	return
+}
+
+func (cs *SparseR1CS) termToString(t compiled.Term, sbb *strings.Builder, vOnly bool) {
+	if !vOnly {
+		tID := t.CoeffID()
+		if tID == compiled.CoeffIdOne {
+			// do nothing, just print the variable
+			sbb.WriteString("1")
+		} else if tID == compiled.CoeffIdMinusOne {
+			// print neg sign
+			sbb.WriteString("-1")
+		} else if tID == compiled.CoeffIdZero {
+			sbb.WriteByte('0')
+			return
+		} else {
+			sbb.WriteString(cs.Coefficients[tID].String())
+		}
+		sbb.WriteString("⋅")
 	}
+
 	vID := t.WireID()
 	visibility := t.VariableVisibility()
 
@@ -303,7 +346,6 @@ func (cs *SparseR1CS) termToString(t compiled.Term) string {
 	default:
 		sbb.WriteString("<?>")
 	}
-	return sbb.String()
 }
 
 // checkConstraint verifies that the constraint holds
@@ -318,12 +360,12 @@ func (cs *SparseR1CS) checkConstraint(c compiled.SparseR1C, solution *solution)
 	var t fr.Element
 	t.Mul(&m0, &m1).Add(&t, &l).Add(&t, &r).Add(&t, &o).Add(&t, &cs.Coefficients[c.K])
 	if !t.IsZero() {
-		return fmt.Errorf("%w\n%s + %s + (%s * %s) + %s + %s != 0", ErrUnsatisfiedConstraint,
+		return fmt.Errorf("qL⋅xa + qR⋅xb + qO⋅xc + qM⋅(xaxb) + qC != 0 → %s + %s + %s + (%s × %s) + %s != 0",
 			l.String(),
 			r.String(),
+			o.String(),
 			m0.String(),
 			m1.String(),
-			o.String(),
 			cs.Coefficients[c.K].String(),
 		)
 	}
@@ -331,39 +373,6 @@ func (cs *SparseR1CS) checkConstraint(c compiled.SparseR1C, solution *solution)
 
 }
 
-// ToHTML returns an HTML human-readable representation of the constraint system
-func (cs *SparseR1CS) ToHTML(w io.Writer) error {
-	t, err := template.New("scs.html").Funcs(template.FuncMap{
-		"toHTML":      toHTMLTerm,
-		"toHTMLCoeff": toHTMLCoeff,
-		"add":         add,
-		"sub":         sub,
-	}).Parse(compiled.SparseR1CSTemplate)
-	if err != nil {
-		return err
-	}
-
-	return t.Execute(w, cs)
-}
-
-func toHTMLTerm(t compiled.Term, coeffs []fr.Element, MHints map[int]compiled.Hint) string {
-	var sbb strings.Builder
-	termToHTML(t, &sbb, coeffs, MHints, true)
-	return sbb.String()
-}
-
-func toHTMLCoeff(cID int, coeffs []fr.Element) string {
-	if cID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		return "<span class=\"coefficient\">-1</span>"
-	}
-	var sbb strings.Builder
-	sbb.WriteString("<span class=\"coefficient\">")
-	sbb.WriteString(coeffs[cID].String())
-	sbb.WriteString("</span>")
-	return sbb.String()
-}
-
 // FrSize return fr.Limbs * 8, size in byte of a fr element
 func (cs *SparseR1CS) FrSize() int {
 	return fr.Limbs * 8
diff --git a/internal/backend/bls12-381/cs/solution.go b/internal/backend/bls12-381/cs/solution.go
index 72c803dae3..255c7721d9 100644
--- a/internal/backend/bls12-381/cs/solution.go
+++ b/internal/backend/bls12-381/cs/solution.go
@@ -33,9 +33,6 @@ import (
 	curve "github.com/consensys/gnark-crypto/ecc/bls12-381"
 )
 
-// ErrUnsatisfiedConstraint can be generated when solving a R1CS
-var ErrUnsatisfiedConstraint = errors.New("constraint is not satisfied")
-
 // solution represents elements needed to compute
 // a solution to a R1CS or SparseR1CS
 type solution struct {
diff --git a/internal/backend/bls24-315/cs/r1cs.go b/internal/backend/bls24-315/cs/r1cs.go
index 7bc054c6ce..aa32a40d8f 100644
--- a/internal/backend/bls24-315/cs/r1cs.go
+++ b/internal/backend/bls24-315/cs/r1cs.go
@@ -32,7 +32,6 @@ import (
 	"github.com/consensys/gnark/internal/backend/ioutils"
 
 	"github.com/consensys/gnark-crypto/ecc"
-	"text/template"
 
 	"github.com/consensys/gnark-crypto/ecc/bls24-315/fr"
 
@@ -119,11 +118,11 @@ func (cs *R1CS) Solve(witness, a, b, c []fr.Element, opt backend.ProverConfig) (
 		// ensure a[i] * b[i] == c[i]
 		check.Mul(&a[i], &b[i])
 		if !check.Equal(&c[i]) {
+			errMsg := fmt.Sprintf("%s ⋅ %s != %s", a[i].String(), b[i].String(), c[i].String())
 			if dID, ok := cs.MDebug[i]; ok {
-				debugInfoStr := solution.logValue(cs.DebugInfo[dID])
-				return solution.values, fmt.Errorf("%w: %s", ErrUnsatisfiedConstraint, debugInfoStr)
+				errMsg = solution.logValue(cs.DebugInfo[dID])
 			}
-			return solution.values, ErrUnsatisfiedConstraint
+			return solution.values, fmt.Errorf("constraint #%d is not satisfied: %s", i, errMsg)
 		}
 	}
 
@@ -289,32 +288,10 @@ func (cs *R1CS) solveConstraint(r compiled.R1C, solution *solution) error {
 	return nil
 }
 
-// TODO @gbotrel clean logs and html see https://github.com/ConsenSys/gnark/issues/140
-
-// ToHTML returns an HTML human-readable representation of the constraint system
-func (cs *R1CS) ToHTML(w io.Writer) error {
-	t, err := template.New("cs.html").Funcs(template.FuncMap{
-		"toHTML": toHTML,
-		"add":    add,
-		"sub":    sub,
-	}).Parse(compiled.R1CSTemplate)
-	if err != nil {
-		return err
-	}
-
-	return t.Execute(w, cs)
-}
-
-func add(a, b int) int {
-	return a + b
-}
-
-func sub(a, b int) int {
-	return a - b
-}
-
+// GetConstraints return a list of constraint formatted as L⋅R == O
+// such that [0] -> L, [1] -> R, [2] -> O
 func (cs *R1CS) GetConstraints() [][]string {
-	var r [][]string
+	r := make([][]string, len(cs.Constraints))
 	for _, c := range cs.Constraints {
 		// for each constraint, we build a string representation of it's L, R and O part
 		// if we are worried about perf for large cs, we could do a string builder + csv format.
@@ -350,7 +327,7 @@ func (cs *R1CS) termToString(t compiled.Term, sbb *strings.Builder) {
 		return
 	} else {
 		sbb.WriteString(cs.Coefficients[tID].String())
-		sbb.WriteByte('*')
+		sbb.WriteString("⋅")
 	}
 	vID := t.WireID()
 	visibility := t.VariableVisibility()
@@ -375,59 +352,6 @@ func (cs *R1CS) termToString(t compiled.Term, sbb *strings.Builder) {
 	}
 }
 
-func toHTML(l compiled.Variable, coeffs []fr.Element, MHints map[int]compiled.Hint) string {
-	var sbb strings.Builder
-	for i := 0; i < len(l.LinExp); i++ {
-		termToHTML(l.LinExp[i], &sbb, coeffs, MHints, false)
-		if i+1 < len(l.LinExp) {
-			sbb.WriteString(" + ")
-		}
-	}
-	return sbb.String()
-}
-
-func termToHTML(t compiled.Term, sbb *strings.Builder, coeffs []fr.Element, MHints map[int]compiled.Hint, offset bool) {
-	tID := t.CoeffID()
-	if tID == compiled.CoeffIdOne {
-		// do nothing, just print the variable
-	} else if tID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		sbb.WriteString("<span class=\"coefficient\">-</span>")
-	} else if tID == compiled.CoeffIdZero {
-		sbb.WriteString("<span class=\"coefficient\">0</span>")
-		return
-	} else {
-		sbb.WriteString("<span class=\"coefficient\">")
-		sbb.WriteString(coeffs[tID].String())
-		sbb.WriteString("</span>*")
-	}
-
-	vID := t.WireID()
-	class := ""
-	switch t.VariableVisibility() {
-	case schema.Internal:
-		class = "internal"
-		if _, ok := MHints[vID]; ok {
-			class = "hint"
-		}
-	case schema.Public:
-		class = "public"
-	case schema.Secret:
-		class = "secret"
-	case schema.Virtual:
-		class = "virtual"
-	case schema.Unset:
-		class = "unset"
-	default:
-		panic("not implemented")
-	}
-	if offset {
-		vID++ // for sparse R1CS, we offset to have same variable numbers as in R1CS
-	}
-	sbb.WriteString(fmt.Sprintf("<span class=\"%s\">v%d</span>", class, vID))
-
-}
-
 // GetNbCoefficients return the number of unique coefficients needed in the R1CS
 func (cs *R1CS) GetNbCoefficients() int {
 	return len(cs.Coefficients)
diff --git a/internal/backend/bls24-315/cs/r1cs_sparse.go b/internal/backend/bls24-315/cs/r1cs_sparse.go
index 759b55c41f..b1bdda70b2 100644
--- a/internal/backend/bls24-315/cs/r1cs_sparse.go
+++ b/internal/backend/bls24-315/cs/r1cs_sparse.go
@@ -24,7 +24,6 @@ import (
 	"math/big"
 	"os"
 	"strings"
-	"text/template"
 
 	"github.com/consensys/gnark/backend"
 	"github.com/consensys/gnark/backend/witness"
@@ -110,11 +109,11 @@ func (cs *SparseR1CS) Solve(witness []fr.Element, opt backend.ProverConfig) ([]f
 			return solution.values, fmt.Errorf("constraint %d: %w", i, err)
 		}
 		if err := cs.checkConstraint(cs.Constraints[i], &solution); err != nil {
+			errMsg := err.Error()
 			if dID, ok := cs.MDebug[i]; ok {
-				debugInfoStr := solution.logValue(cs.DebugInfo[dID])
-				return solution.values, fmt.Errorf("%w: %s", ErrUnsatisfiedConstraint, debugInfoStr)
+				errMsg = solution.logValue(cs.DebugInfo[dID])
 			}
-			return solution.values, ErrUnsatisfiedConstraint
+			return solution.values, fmt.Errorf("constraint #%d is not satisfied: %s", i, errMsg)
 		}
 	}
 
@@ -255,37 +254,81 @@ func (cs *SparseR1CS) IsSolved(witness *witness.Witness, opts ...backend.ProverO
 	return err
 }
 
+// GetConstraints return a list of constraint formatted as in the paper
+// https://eprint.iacr.org/2019/953.pdf section 6 such that
+// qL⋅xa + qR⋅xb + qO⋅xc + qM⋅(xaxb) + qC == 0
+// each constraint is thus decomposed in [5]string with
+// 		[0] = qL⋅xa
+//		[1] = qR⋅xb
+//		[2] = qO⋅xc
+//		[3] = qM⋅(xaxb)
+//		[4] = qC
 func (cs *SparseR1CS) GetConstraints() [][]string {
-	var r [][]string
+	r := make([][]string, 0, len(cs.Constraints))
 	for _, c := range cs.Constraints {
-		// if we are worried about perf for large cs, we could do a string builder + csv format.
-		var line [6]string
-		line[0] = cs.termToString(c.L)
-		line[1] = cs.termToString(c.R)
-		line[2] = cs.termToString(c.M[0])
-		line[3] = cs.termToString(c.M[1])
-		line[4] = cs.termToString(c.O)
-		line[5] = cs.Coefficients[c.K].String()
-		r = append(r, line[:])
+		fc := cs.formatConstraint(c)
+		r = append(r, fc[:])
 	}
 	return r
 }
 
-func (cs *SparseR1CS) termToString(t compiled.Term) string {
+// r[0] = qL⋅xa
+// r[1] = qR⋅xb
+// r[2] = qO⋅xc
+// r[3] = qM⋅(xaxb)
+// r[4] = qC
+func (cs *SparseR1CS) formatConstraint(c compiled.SparseR1C) (r [5]string) {
+	isZeroM := (c.M[0].CoeffID() == compiled.CoeffIdZero) && (c.M[1].CoeffID() == compiled.CoeffIdZero)
+
 	var sbb strings.Builder
-	tID := t.CoeffID()
-	if tID == compiled.CoeffIdOne {
-		// do nothing, just print the variable
-	} else if tID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		sbb.WriteByte('-')
-	} else if tID == compiled.CoeffIdZero {
-		sbb.WriteByte('0')
-		return sbb.String()
+	cs.termToString(c.L, &sbb, false)
+	r[0] = sbb.String()
+
+	sbb.Reset()
+	cs.termToString(c.R, &sbb, false)
+	r[1] = sbb.String()
+
+	sbb.Reset()
+	cs.termToString(c.O, &sbb, false)
+	r[2] = sbb.String()
+
+	if isZeroM {
+		r[3] = "0"
 	} else {
-		sbb.WriteString(cs.Coefficients[tID].String())
-		sbb.WriteByte('*')
+		sbb.Reset()
+		sbb.WriteString(cs.Coefficients[c.M[0].CoeffID()].String())
+		sbb.WriteString("⋅")
+		sbb.WriteByte('(')
+		cs.termToString(c.M[0], &sbb, true)
+		sbb.WriteString(" × ")
+		cs.termToString(c.M[1], &sbb, true)
+		sbb.WriteByte(')')
+		r[3] = sbb.String()
+	}
+
+	r[4] = cs.Coefficients[c.K].String()
+
+	return
+}
+
+func (cs *SparseR1CS) termToString(t compiled.Term, sbb *strings.Builder, vOnly bool) {
+	if !vOnly {
+		tID := t.CoeffID()
+		if tID == compiled.CoeffIdOne {
+			// do nothing, just print the variable
+			sbb.WriteString("1")
+		} else if tID == compiled.CoeffIdMinusOne {
+			// print neg sign
+			sbb.WriteString("-1")
+		} else if tID == compiled.CoeffIdZero {
+			sbb.WriteByte('0')
+			return
+		} else {
+			sbb.WriteString(cs.Coefficients[tID].String())
+		}
+		sbb.WriteString("⋅")
 	}
+
 	vID := t.WireID()
 	visibility := t.VariableVisibility()
 
@@ -303,7 +346,6 @@ func (cs *SparseR1CS) termToString(t compiled.Term) string {
 	default:
 		sbb.WriteString("<?>")
 	}
-	return sbb.String()
 }
 
 // checkConstraint verifies that the constraint holds
@@ -318,12 +360,12 @@ func (cs *SparseR1CS) checkConstraint(c compiled.SparseR1C, solution *solution)
 	var t fr.Element
 	t.Mul(&m0, &m1).Add(&t, &l).Add(&t, &r).Add(&t, &o).Add(&t, &cs.Coefficients[c.K])
 	if !t.IsZero() {
-		return fmt.Errorf("%w\n%s + %s + (%s * %s) + %s + %s != 0", ErrUnsatisfiedConstraint,
+		return fmt.Errorf("qL⋅xa + qR⋅xb + qO⋅xc + qM⋅(xaxb) + qC != 0 → %s + %s + %s + (%s × %s) + %s != 0",
 			l.String(),
 			r.String(),
+			o.String(),
 			m0.String(),
 			m1.String(),
-			o.String(),
 			cs.Coefficients[c.K].String(),
 		)
 	}
@@ -331,39 +373,6 @@ func (cs *SparseR1CS) checkConstraint(c compiled.SparseR1C, solution *solution)
 
 }
 
-// ToHTML returns an HTML human-readable representation of the constraint system
-func (cs *SparseR1CS) ToHTML(w io.Writer) error {
-	t, err := template.New("scs.html").Funcs(template.FuncMap{
-		"toHTML":      toHTMLTerm,
-		"toHTMLCoeff": toHTMLCoeff,
-		"add":         add,
-		"sub":         sub,
-	}).Parse(compiled.SparseR1CSTemplate)
-	if err != nil {
-		return err
-	}
-
-	return t.Execute(w, cs)
-}
-
-func toHTMLTerm(t compiled.Term, coeffs []fr.Element, MHints map[int]compiled.Hint) string {
-	var sbb strings.Builder
-	termToHTML(t, &sbb, coeffs, MHints, true)
-	return sbb.String()
-}
-
-func toHTMLCoeff(cID int, coeffs []fr.Element) string {
-	if cID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		return "<span class=\"coefficient\">-1</span>"
-	}
-	var sbb strings.Builder
-	sbb.WriteString("<span class=\"coefficient\">")
-	sbb.WriteString(coeffs[cID].String())
-	sbb.WriteString("</span>")
-	return sbb.String()
-}
-
 // FrSize return fr.Limbs * 8, size in byte of a fr element
 func (cs *SparseR1CS) FrSize() int {
 	return fr.Limbs * 8
diff --git a/internal/backend/bls24-315/cs/solution.go b/internal/backend/bls24-315/cs/solution.go
index a457362c51..b69f343696 100644
--- a/internal/backend/bls24-315/cs/solution.go
+++ b/internal/backend/bls24-315/cs/solution.go
@@ -33,9 +33,6 @@ import (
 	curve "github.com/consensys/gnark-crypto/ecc/bls24-315"
 )
 
-// ErrUnsatisfiedConstraint can be generated when solving a R1CS
-var ErrUnsatisfiedConstraint = errors.New("constraint is not satisfied")
-
 // solution represents elements needed to compute
 // a solution to a R1CS or SparseR1CS
 type solution struct {
diff --git a/internal/backend/bn254/cs/r1cs.go b/internal/backend/bn254/cs/r1cs.go
index 554a461f4e..e6e45b2116 100644
--- a/internal/backend/bn254/cs/r1cs.go
+++ b/internal/backend/bn254/cs/r1cs.go
@@ -32,7 +32,6 @@ import (
 	"github.com/consensys/gnark/internal/backend/ioutils"
 
 	"github.com/consensys/gnark-crypto/ecc"
-	"text/template"
 
 	"github.com/consensys/gnark-crypto/ecc/bn254/fr"
 
@@ -119,11 +118,11 @@ func (cs *R1CS) Solve(witness, a, b, c []fr.Element, opt backend.ProverConfig) (
 		// ensure a[i] * b[i] == c[i]
 		check.Mul(&a[i], &b[i])
 		if !check.Equal(&c[i]) {
+			errMsg := fmt.Sprintf("%s ⋅ %s != %s", a[i].String(), b[i].String(), c[i].String())
 			if dID, ok := cs.MDebug[i]; ok {
-				debugInfoStr := solution.logValue(cs.DebugInfo[dID])
-				return solution.values, fmt.Errorf("%w: %s", ErrUnsatisfiedConstraint, debugInfoStr)
+				errMsg = solution.logValue(cs.DebugInfo[dID])
 			}
-			return solution.values, ErrUnsatisfiedConstraint
+			return solution.values, fmt.Errorf("constraint #%d is not satisfied: %s", i, errMsg)
 		}
 	}
 
@@ -289,32 +288,10 @@ func (cs *R1CS) solveConstraint(r compiled.R1C, solution *solution) error {
 	return nil
 }
 
-// TODO @gbotrel clean logs and html see https://github.com/ConsenSys/gnark/issues/140
-
-// ToHTML returns an HTML human-readable representation of the constraint system
-func (cs *R1CS) ToHTML(w io.Writer) error {
-	t, err := template.New("cs.html").Funcs(template.FuncMap{
-		"toHTML": toHTML,
-		"add":    add,
-		"sub":    sub,
-	}).Parse(compiled.R1CSTemplate)
-	if err != nil {
-		return err
-	}
-
-	return t.Execute(w, cs)
-}
-
-func add(a, b int) int {
-	return a + b
-}
-
-func sub(a, b int) int {
-	return a - b
-}
-
+// GetConstraints return a list of constraint formatted as L⋅R == O
+// such that [0] -> L, [1] -> R, [2] -> O
 func (cs *R1CS) GetConstraints() [][]string {
-	var r [][]string
+	r := make([][]string, len(cs.Constraints))
 	for _, c := range cs.Constraints {
 		// for each constraint, we build a string representation of it's L, R and O part
 		// if we are worried about perf for large cs, we could do a string builder + csv format.
@@ -350,7 +327,7 @@ func (cs *R1CS) termToString(t compiled.Term, sbb *strings.Builder) {
 		return
 	} else {
 		sbb.WriteString(cs.Coefficients[tID].String())
-		sbb.WriteByte('*')
+		sbb.WriteString("⋅")
 	}
 	vID := t.WireID()
 	visibility := t.VariableVisibility()
@@ -375,59 +352,6 @@ func (cs *R1CS) termToString(t compiled.Term, sbb *strings.Builder) {
 	}
 }
 
-func toHTML(l compiled.Variable, coeffs []fr.Element, MHints map[int]compiled.Hint) string {
-	var sbb strings.Builder
-	for i := 0; i < len(l.LinExp); i++ {
-		termToHTML(l.LinExp[i], &sbb, coeffs, MHints, false)
-		if i+1 < len(l.LinExp) {
-			sbb.WriteString(" + ")
-		}
-	}
-	return sbb.String()
-}
-
-func termToHTML(t compiled.Term, sbb *strings.Builder, coeffs []fr.Element, MHints map[int]compiled.Hint, offset bool) {
-	tID := t.CoeffID()
-	if tID == compiled.CoeffIdOne {
-		// do nothing, just print the variable
-	} else if tID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		sbb.WriteString("<span class=\"coefficient\">-</span>")
-	} else if tID == compiled.CoeffIdZero {
-		sbb.WriteString("<span class=\"coefficient\">0</span>")
-		return
-	} else {
-		sbb.WriteString("<span class=\"coefficient\">")
-		sbb.WriteString(coeffs[tID].String())
-		sbb.WriteString("</span>*")
-	}
-
-	vID := t.WireID()
-	class := ""
-	switch t.VariableVisibility() {
-	case schema.Internal:
-		class = "internal"
-		if _, ok := MHints[vID]; ok {
-			class = "hint"
-		}
-	case schema.Public:
-		class = "public"
-	case schema.Secret:
-		class = "secret"
-	case schema.Virtual:
-		class = "virtual"
-	case schema.Unset:
-		class = "unset"
-	default:
-		panic("not implemented")
-	}
-	if offset {
-		vID++ // for sparse R1CS, we offset to have same variable numbers as in R1CS
-	}
-	sbb.WriteString(fmt.Sprintf("<span class=\"%s\">v%d</span>", class, vID))
-
-}
-
 // GetNbCoefficients return the number of unique coefficients needed in the R1CS
 func (cs *R1CS) GetNbCoefficients() int {
 	return len(cs.Coefficients)
diff --git a/internal/backend/bn254/cs/r1cs_sparse.go b/internal/backend/bn254/cs/r1cs_sparse.go
index cc4cbfd833..fa3a146d1e 100644
--- a/internal/backend/bn254/cs/r1cs_sparse.go
+++ b/internal/backend/bn254/cs/r1cs_sparse.go
@@ -24,7 +24,6 @@ import (
 	"math/big"
 	"os"
 	"strings"
-	"text/template"
 
 	"github.com/consensys/gnark/backend"
 	"github.com/consensys/gnark/backend/witness"
@@ -110,11 +109,11 @@ func (cs *SparseR1CS) Solve(witness []fr.Element, opt backend.ProverConfig) ([]f
 			return solution.values, fmt.Errorf("constraint %d: %w", i, err)
 		}
 		if err := cs.checkConstraint(cs.Constraints[i], &solution); err != nil {
+			errMsg := err.Error()
 			if dID, ok := cs.MDebug[i]; ok {
-				debugInfoStr := solution.logValue(cs.DebugInfo[dID])
-				return solution.values, fmt.Errorf("%w: %s", ErrUnsatisfiedConstraint, debugInfoStr)
+				errMsg = solution.logValue(cs.DebugInfo[dID])
 			}
-			return solution.values, ErrUnsatisfiedConstraint
+			return solution.values, fmt.Errorf("constraint #%d is not satisfied: %s", i, errMsg)
 		}
 	}
 
@@ -255,37 +254,81 @@ func (cs *SparseR1CS) IsSolved(witness *witness.Witness, opts ...backend.ProverO
 	return err
 }
 
+// GetConstraints return a list of constraint formatted as in the paper
+// https://eprint.iacr.org/2019/953.pdf section 6 such that
+// qL⋅xa + qR⋅xb + qO⋅xc + qM⋅(xaxb) + qC == 0
+// each constraint is thus decomposed in [5]string with
+// 		[0] = qL⋅xa
+//		[1] = qR⋅xb
+//		[2] = qO⋅xc
+//		[3] = qM⋅(xaxb)
+//		[4] = qC
 func (cs *SparseR1CS) GetConstraints() [][]string {
-	var r [][]string
+	r := make([][]string, 0, len(cs.Constraints))
 	for _, c := range cs.Constraints {
-		// if we are worried about perf for large cs, we could do a string builder + csv format.
-		var line [6]string
-		line[0] = cs.termToString(c.L)
-		line[1] = cs.termToString(c.R)
-		line[2] = cs.termToString(c.M[0])
-		line[3] = cs.termToString(c.M[1])
-		line[4] = cs.termToString(c.O)
-		line[5] = cs.Coefficients[c.K].String()
-		r = append(r, line[:])
+		fc := cs.formatConstraint(c)
+		r = append(r, fc[:])
 	}
 	return r
 }
 
-func (cs *SparseR1CS) termToString(t compiled.Term) string {
+// r[0] = qL⋅xa
+// r[1] = qR⋅xb
+// r[2] = qO⋅xc
+// r[3] = qM⋅(xaxb)
+// r[4] = qC
+func (cs *SparseR1CS) formatConstraint(c compiled.SparseR1C) (r [5]string) {
+	isZeroM := (c.M[0].CoeffID() == compiled.CoeffIdZero) && (c.M[1].CoeffID() == compiled.CoeffIdZero)
+
 	var sbb strings.Builder
-	tID := t.CoeffID()
-	if tID == compiled.CoeffIdOne {
-		// do nothing, just print the variable
-	} else if tID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		sbb.WriteByte('-')
-	} else if tID == compiled.CoeffIdZero {
-		sbb.WriteByte('0')
-		return sbb.String()
+	cs.termToString(c.L, &sbb, false)
+	r[0] = sbb.String()
+
+	sbb.Reset()
+	cs.termToString(c.R, &sbb, false)
+	r[1] = sbb.String()
+
+	sbb.Reset()
+	cs.termToString(c.O, &sbb, false)
+	r[2] = sbb.String()
+
+	if isZeroM {
+		r[3] = "0"
 	} else {
-		sbb.WriteString(cs.Coefficients[tID].String())
-		sbb.WriteByte('*')
+		sbb.Reset()
+		sbb.WriteString(cs.Coefficients[c.M[0].CoeffID()].String())
+		sbb.WriteString("⋅")
+		sbb.WriteByte('(')
+		cs.termToString(c.M[0], &sbb, true)
+		sbb.WriteString(" × ")
+		cs.termToString(c.M[1], &sbb, true)
+		sbb.WriteByte(')')
+		r[3] = sbb.String()
+	}
+
+	r[4] = cs.Coefficients[c.K].String()
+
+	return
+}
+
+func (cs *SparseR1CS) termToString(t compiled.Term, sbb *strings.Builder, vOnly bool) {
+	if !vOnly {
+		tID := t.CoeffID()
+		if tID == compiled.CoeffIdOne {
+			// do nothing, just print the variable
+			sbb.WriteString("1")
+		} else if tID == compiled.CoeffIdMinusOne {
+			// print neg sign
+			sbb.WriteString("-1")
+		} else if tID == compiled.CoeffIdZero {
+			sbb.WriteByte('0')
+			return
+		} else {
+			sbb.WriteString(cs.Coefficients[tID].String())
+		}
+		sbb.WriteString("⋅")
 	}
+
 	vID := t.WireID()
 	visibility := t.VariableVisibility()
 
@@ -303,7 +346,6 @@ func (cs *SparseR1CS) termToString(t compiled.Term) string {
 	default:
 		sbb.WriteString("<?>")
 	}
-	return sbb.String()
 }
 
 // checkConstraint verifies that the constraint holds
@@ -318,12 +360,12 @@ func (cs *SparseR1CS) checkConstraint(c compiled.SparseR1C, solution *solution)
 	var t fr.Element
 	t.Mul(&m0, &m1).Add(&t, &l).Add(&t, &r).Add(&t, &o).Add(&t, &cs.Coefficients[c.K])
 	if !t.IsZero() {
-		return fmt.Errorf("%w\n%s + %s + (%s * %s) + %s + %s != 0", ErrUnsatisfiedConstraint,
+		return fmt.Errorf("qL⋅xa + qR⋅xb + qO⋅xc + qM⋅(xaxb) + qC != 0 → %s + %s + %s + (%s × %s) + %s != 0",
 			l.String(),
 			r.String(),
+			o.String(),
 			m0.String(),
 			m1.String(),
-			o.String(),
 			cs.Coefficients[c.K].String(),
 		)
 	}
@@ -331,39 +373,6 @@ func (cs *SparseR1CS) checkConstraint(c compiled.SparseR1C, solution *solution)
 
 }
 
-// ToHTML returns an HTML human-readable representation of the constraint system
-func (cs *SparseR1CS) ToHTML(w io.Writer) error {
-	t, err := template.New("scs.html").Funcs(template.FuncMap{
-		"toHTML":      toHTMLTerm,
-		"toHTMLCoeff": toHTMLCoeff,
-		"add":         add,
-		"sub":         sub,
-	}).Parse(compiled.SparseR1CSTemplate)
-	if err != nil {
-		return err
-	}
-
-	return t.Execute(w, cs)
-}
-
-func toHTMLTerm(t compiled.Term, coeffs []fr.Element, MHints map[int]compiled.Hint) string {
-	var sbb strings.Builder
-	termToHTML(t, &sbb, coeffs, MHints, true)
-	return sbb.String()
-}
-
-func toHTMLCoeff(cID int, coeffs []fr.Element) string {
-	if cID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		return "<span class=\"coefficient\">-1</span>"
-	}
-	var sbb strings.Builder
-	sbb.WriteString("<span class=\"coefficient\">")
-	sbb.WriteString(coeffs[cID].String())
-	sbb.WriteString("</span>")
-	return sbb.String()
-}
-
 // FrSize return fr.Limbs * 8, size in byte of a fr element
 func (cs *SparseR1CS) FrSize() int {
 	return fr.Limbs * 8
diff --git a/internal/backend/bn254/cs/solution.go b/internal/backend/bn254/cs/solution.go
index 7061493101..f4dff4d854 100644
--- a/internal/backend/bn254/cs/solution.go
+++ b/internal/backend/bn254/cs/solution.go
@@ -33,9 +33,6 @@ import (
 	curve "github.com/consensys/gnark-crypto/ecc/bn254"
 )
 
-// ErrUnsatisfiedConstraint can be generated when solving a R1CS
-var ErrUnsatisfiedConstraint = errors.New("constraint is not satisfied")
-
 // solution represents elements needed to compute
 // a solution to a R1CS or SparseR1CS
 type solution struct {
diff --git a/internal/backend/bw6-633/cs/r1cs.go b/internal/backend/bw6-633/cs/r1cs.go
index 20e19fb5bd..441905ff6e 100644
--- a/internal/backend/bw6-633/cs/r1cs.go
+++ b/internal/backend/bw6-633/cs/r1cs.go
@@ -32,7 +32,6 @@ import (
 	"github.com/consensys/gnark/internal/backend/ioutils"
 
 	"github.com/consensys/gnark-crypto/ecc"
-	"text/template"
 
 	"github.com/consensys/gnark-crypto/ecc/bw6-633/fr"
 
@@ -119,11 +118,11 @@ func (cs *R1CS) Solve(witness, a, b, c []fr.Element, opt backend.ProverConfig) (
 		// ensure a[i] * b[i] == c[i]
 		check.Mul(&a[i], &b[i])
 		if !check.Equal(&c[i]) {
+			errMsg := fmt.Sprintf("%s ⋅ %s != %s", a[i].String(), b[i].String(), c[i].String())
 			if dID, ok := cs.MDebug[i]; ok {
-				debugInfoStr := solution.logValue(cs.DebugInfo[dID])
-				return solution.values, fmt.Errorf("%w: %s", ErrUnsatisfiedConstraint, debugInfoStr)
+				errMsg = solution.logValue(cs.DebugInfo[dID])
 			}
-			return solution.values, ErrUnsatisfiedConstraint
+			return solution.values, fmt.Errorf("constraint #%d is not satisfied: %s", i, errMsg)
 		}
 	}
 
@@ -289,32 +288,10 @@ func (cs *R1CS) solveConstraint(r compiled.R1C, solution *solution) error {
 	return nil
 }
 
-// TODO @gbotrel clean logs and html see https://github.com/ConsenSys/gnark/issues/140
-
-// ToHTML returns an HTML human-readable representation of the constraint system
-func (cs *R1CS) ToHTML(w io.Writer) error {
-	t, err := template.New("cs.html").Funcs(template.FuncMap{
-		"toHTML": toHTML,
-		"add":    add,
-		"sub":    sub,
-	}).Parse(compiled.R1CSTemplate)
-	if err != nil {
-		return err
-	}
-
-	return t.Execute(w, cs)
-}
-
-func add(a, b int) int {
-	return a + b
-}
-
-func sub(a, b int) int {
-	return a - b
-}
-
+// GetConstraints return a list of constraint formatted as L⋅R == O
+// such that [0] -> L, [1] -> R, [2] -> O
 func (cs *R1CS) GetConstraints() [][]string {
-	var r [][]string
+	r := make([][]string, len(cs.Constraints))
 	for _, c := range cs.Constraints {
 		// for each constraint, we build a string representation of it's L, R and O part
 		// if we are worried about perf for large cs, we could do a string builder + csv format.
@@ -350,7 +327,7 @@ func (cs *R1CS) termToString(t compiled.Term, sbb *strings.Builder) {
 		return
 	} else {
 		sbb.WriteString(cs.Coefficients[tID].String())
-		sbb.WriteByte('*')
+		sbb.WriteString("⋅")
 	}
 	vID := t.WireID()
 	visibility := t.VariableVisibility()
@@ -375,59 +352,6 @@ func (cs *R1CS) termToString(t compiled.Term, sbb *strings.Builder) {
 	}
 }
 
-func toHTML(l compiled.Variable, coeffs []fr.Element, MHints map[int]compiled.Hint) string {
-	var sbb strings.Builder
-	for i := 0; i < len(l.LinExp); i++ {
-		termToHTML(l.LinExp[i], &sbb, coeffs, MHints, false)
-		if i+1 < len(l.LinExp) {
-			sbb.WriteString(" + ")
-		}
-	}
-	return sbb.String()
-}
-
-func termToHTML(t compiled.Term, sbb *strings.Builder, coeffs []fr.Element, MHints map[int]compiled.Hint, offset bool) {
-	tID := t.CoeffID()
-	if tID == compiled.CoeffIdOne {
-		// do nothing, just print the variable
-	} else if tID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		sbb.WriteString("<span class=\"coefficient\">-</span>")
-	} else if tID == compiled.CoeffIdZero {
-		sbb.WriteString("<span class=\"coefficient\">0</span>")
-		return
-	} else {
-		sbb.WriteString("<span class=\"coefficient\">")
-		sbb.WriteString(coeffs[tID].String())
-		sbb.WriteString("</span>*")
-	}
-
-	vID := t.WireID()
-	class := ""
-	switch t.VariableVisibility() {
-	case schema.Internal:
-		class = "internal"
-		if _, ok := MHints[vID]; ok {
-			class = "hint"
-		}
-	case schema.Public:
-		class = "public"
-	case schema.Secret:
-		class = "secret"
-	case schema.Virtual:
-		class = "virtual"
-	case schema.Unset:
-		class = "unset"
-	default:
-		panic("not implemented")
-	}
-	if offset {
-		vID++ // for sparse R1CS, we offset to have same variable numbers as in R1CS
-	}
-	sbb.WriteString(fmt.Sprintf("<span class=\"%s\">v%d</span>", class, vID))
-
-}
-
 // GetNbCoefficients return the number of unique coefficients needed in the R1CS
 func (cs *R1CS) GetNbCoefficients() int {
 	return len(cs.Coefficients)
diff --git a/internal/backend/bw6-633/cs/r1cs_sparse.go b/internal/backend/bw6-633/cs/r1cs_sparse.go
index a63dc66b11..b014842de1 100644
--- a/internal/backend/bw6-633/cs/r1cs_sparse.go
+++ b/internal/backend/bw6-633/cs/r1cs_sparse.go
@@ -24,7 +24,6 @@ import (
 	"math/big"
 	"os"
 	"strings"
-	"text/template"
 
 	"github.com/consensys/gnark/backend"
 	"github.com/consensys/gnark/backend/witness"
@@ -110,11 +109,11 @@ func (cs *SparseR1CS) Solve(witness []fr.Element, opt backend.ProverConfig) ([]f
 			return solution.values, fmt.Errorf("constraint %d: %w", i, err)
 		}
 		if err := cs.checkConstraint(cs.Constraints[i], &solution); err != nil {
+			errMsg := err.Error()
 			if dID, ok := cs.MDebug[i]; ok {
-				debugInfoStr := solution.logValue(cs.DebugInfo[dID])
-				return solution.values, fmt.Errorf("%w: %s", ErrUnsatisfiedConstraint, debugInfoStr)
+				errMsg = solution.logValue(cs.DebugInfo[dID])
 			}
-			return solution.values, ErrUnsatisfiedConstraint
+			return solution.values, fmt.Errorf("constraint #%d is not satisfied: %s", i, errMsg)
 		}
 	}
 
@@ -255,37 +254,81 @@ func (cs *SparseR1CS) IsSolved(witness *witness.Witness, opts ...backend.ProverO
 	return err
 }
 
+// GetConstraints return a list of constraint formatted as in the paper
+// https://eprint.iacr.org/2019/953.pdf section 6 such that
+// qL⋅xa + qR⋅xb + qO⋅xc + qM⋅(xaxb) + qC == 0
+// each constraint is thus decomposed in [5]string with
+// 		[0] = qL⋅xa
+//		[1] = qR⋅xb
+//		[2] = qO⋅xc
+//		[3] = qM⋅(xaxb)
+//		[4] = qC
 func (cs *SparseR1CS) GetConstraints() [][]string {
-	var r [][]string
+	r := make([][]string, 0, len(cs.Constraints))
 	for _, c := range cs.Constraints {
-		// if we are worried about perf for large cs, we could do a string builder + csv format.
-		var line [6]string
-		line[0] = cs.termToString(c.L)
-		line[1] = cs.termToString(c.R)
-		line[2] = cs.termToString(c.M[0])
-		line[3] = cs.termToString(c.M[1])
-		line[4] = cs.termToString(c.O)
-		line[5] = cs.Coefficients[c.K].String()
-		r = append(r, line[:])
+		fc := cs.formatConstraint(c)
+		r = append(r, fc[:])
 	}
 	return r
 }
 
-func (cs *SparseR1CS) termToString(t compiled.Term) string {
+// r[0] = qL⋅xa
+// r[1] = qR⋅xb
+// r[2] = qO⋅xc
+// r[3] = qM⋅(xaxb)
+// r[4] = qC
+func (cs *SparseR1CS) formatConstraint(c compiled.SparseR1C) (r [5]string) {
+	isZeroM := (c.M[0].CoeffID() == compiled.CoeffIdZero) && (c.M[1].CoeffID() == compiled.CoeffIdZero)
+
 	var sbb strings.Builder
-	tID := t.CoeffID()
-	if tID == compiled.CoeffIdOne {
-		// do nothing, just print the variable
-	} else if tID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		sbb.WriteByte('-')
-	} else if tID == compiled.CoeffIdZero {
-		sbb.WriteByte('0')
-		return sbb.String()
+	cs.termToString(c.L, &sbb, false)
+	r[0] = sbb.String()
+
+	sbb.Reset()
+	cs.termToString(c.R, &sbb, false)
+	r[1] = sbb.String()
+
+	sbb.Reset()
+	cs.termToString(c.O, &sbb, false)
+	r[2] = sbb.String()
+
+	if isZeroM {
+		r[3] = "0"
 	} else {
-		sbb.WriteString(cs.Coefficients[tID].String())
-		sbb.WriteByte('*')
+		sbb.Reset()
+		sbb.WriteString(cs.Coefficients[c.M[0].CoeffID()].String())
+		sbb.WriteString("⋅")
+		sbb.WriteByte('(')
+		cs.termToString(c.M[0], &sbb, true)
+		sbb.WriteString(" × ")
+		cs.termToString(c.M[1], &sbb, true)
+		sbb.WriteByte(')')
+		r[3] = sbb.String()
+	}
+
+	r[4] = cs.Coefficients[c.K].String()
+
+	return
+}
+
+func (cs *SparseR1CS) termToString(t compiled.Term, sbb *strings.Builder, vOnly bool) {
+	if !vOnly {
+		tID := t.CoeffID()
+		if tID == compiled.CoeffIdOne {
+			// do nothing, just print the variable
+			sbb.WriteString("1")
+		} else if tID == compiled.CoeffIdMinusOne {
+			// print neg sign
+			sbb.WriteString("-1")
+		} else if tID == compiled.CoeffIdZero {
+			sbb.WriteByte('0')
+			return
+		} else {
+			sbb.WriteString(cs.Coefficients[tID].String())
+		}
+		sbb.WriteString("⋅")
 	}
+
 	vID := t.WireID()
 	visibility := t.VariableVisibility()
 
@@ -303,7 +346,6 @@ func (cs *SparseR1CS) termToString(t compiled.Term) string {
 	default:
 		sbb.WriteString("<?>")
 	}
-	return sbb.String()
 }
 
 // checkConstraint verifies that the constraint holds
@@ -318,12 +360,12 @@ func (cs *SparseR1CS) checkConstraint(c compiled.SparseR1C, solution *solution)
 	var t fr.Element
 	t.Mul(&m0, &m1).Add(&t, &l).Add(&t, &r).Add(&t, &o).Add(&t, &cs.Coefficients[c.K])
 	if !t.IsZero() {
-		return fmt.Errorf("%w\n%s + %s + (%s * %s) + %s + %s != 0", ErrUnsatisfiedConstraint,
+		return fmt.Errorf("qL⋅xa + qR⋅xb + qO⋅xc + qM⋅(xaxb) + qC != 0 → %s + %s + %s + (%s × %s) + %s != 0",
 			l.String(),
 			r.String(),
+			o.String(),
 			m0.String(),
 			m1.String(),
-			o.String(),
 			cs.Coefficients[c.K].String(),
 		)
 	}
@@ -331,39 +373,6 @@ func (cs *SparseR1CS) checkConstraint(c compiled.SparseR1C, solution *solution)
 
 }
 
-// ToHTML returns an HTML human-readable representation of the constraint system
-func (cs *SparseR1CS) ToHTML(w io.Writer) error {
-	t, err := template.New("scs.html").Funcs(template.FuncMap{
-		"toHTML":      toHTMLTerm,
-		"toHTMLCoeff": toHTMLCoeff,
-		"add":         add,
-		"sub":         sub,
-	}).Parse(compiled.SparseR1CSTemplate)
-	if err != nil {
-		return err
-	}
-
-	return t.Execute(w, cs)
-}
-
-func toHTMLTerm(t compiled.Term, coeffs []fr.Element, MHints map[int]compiled.Hint) string {
-	var sbb strings.Builder
-	termToHTML(t, &sbb, coeffs, MHints, true)
-	return sbb.String()
-}
-
-func toHTMLCoeff(cID int, coeffs []fr.Element) string {
-	if cID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		return "<span class=\"coefficient\">-1</span>"
-	}
-	var sbb strings.Builder
-	sbb.WriteString("<span class=\"coefficient\">")
-	sbb.WriteString(coeffs[cID].String())
-	sbb.WriteString("</span>")
-	return sbb.String()
-}
-
 // FrSize return fr.Limbs * 8, size in byte of a fr element
 func (cs *SparseR1CS) FrSize() int {
 	return fr.Limbs * 8
diff --git a/internal/backend/bw6-633/cs/solution.go b/internal/backend/bw6-633/cs/solution.go
index a3cca08dd0..d8c2e5c824 100644
--- a/internal/backend/bw6-633/cs/solution.go
+++ b/internal/backend/bw6-633/cs/solution.go
@@ -33,9 +33,6 @@ import (
 	curve "github.com/consensys/gnark-crypto/ecc/bw6-633"
 )
 
-// ErrUnsatisfiedConstraint can be generated when solving a R1CS
-var ErrUnsatisfiedConstraint = errors.New("constraint is not satisfied")
-
 // solution represents elements needed to compute
 // a solution to a R1CS or SparseR1CS
 type solution struct {
diff --git a/internal/backend/bw6-761/cs/r1cs.go b/internal/backend/bw6-761/cs/r1cs.go
index 7a857ab11e..81b561f198 100644
--- a/internal/backend/bw6-761/cs/r1cs.go
+++ b/internal/backend/bw6-761/cs/r1cs.go
@@ -32,7 +32,6 @@ import (
 	"github.com/consensys/gnark/internal/backend/ioutils"
 
 	"github.com/consensys/gnark-crypto/ecc"
-	"text/template"
 
 	"github.com/consensys/gnark-crypto/ecc/bw6-761/fr"
 
@@ -119,11 +118,11 @@ func (cs *R1CS) Solve(witness, a, b, c []fr.Element, opt backend.ProverConfig) (
 		// ensure a[i] * b[i] == c[i]
 		check.Mul(&a[i], &b[i])
 		if !check.Equal(&c[i]) {
+			errMsg := fmt.Sprintf("%s ⋅ %s != %s", a[i].String(), b[i].String(), c[i].String())
 			if dID, ok := cs.MDebug[i]; ok {
-				debugInfoStr := solution.logValue(cs.DebugInfo[dID])
-				return solution.values, fmt.Errorf("%w: %s", ErrUnsatisfiedConstraint, debugInfoStr)
+				errMsg = solution.logValue(cs.DebugInfo[dID])
 			}
-			return solution.values, ErrUnsatisfiedConstraint
+			return solution.values, fmt.Errorf("constraint #%d is not satisfied: %s", i, errMsg)
 		}
 	}
 
@@ -289,32 +288,10 @@ func (cs *R1CS) solveConstraint(r compiled.R1C, solution *solution) error {
 	return nil
 }
 
-// TODO @gbotrel clean logs and html see https://github.com/ConsenSys/gnark/issues/140
-
-// ToHTML returns an HTML human-readable representation of the constraint system
-func (cs *R1CS) ToHTML(w io.Writer) error {
-	t, err := template.New("cs.html").Funcs(template.FuncMap{
-		"toHTML": toHTML,
-		"add":    add,
-		"sub":    sub,
-	}).Parse(compiled.R1CSTemplate)
-	if err != nil {
-		return err
-	}
-
-	return t.Execute(w, cs)
-}
-
-func add(a, b int) int {
-	return a + b
-}
-
-func sub(a, b int) int {
-	return a - b
-}
-
+// GetConstraints return a list of constraint formatted as L⋅R == O
+// such that [0] -> L, [1] -> R, [2] -> O
 func (cs *R1CS) GetConstraints() [][]string {
-	var r [][]string
+	r := make([][]string, len(cs.Constraints))
 	for _, c := range cs.Constraints {
 		// for each constraint, we build a string representation of it's L, R and O part
 		// if we are worried about perf for large cs, we could do a string builder + csv format.
@@ -350,7 +327,7 @@ func (cs *R1CS) termToString(t compiled.Term, sbb *strings.Builder) {
 		return
 	} else {
 		sbb.WriteString(cs.Coefficients[tID].String())
-		sbb.WriteByte('*')
+		sbb.WriteString("⋅")
 	}
 	vID := t.WireID()
 	visibility := t.VariableVisibility()
@@ -375,59 +352,6 @@ func (cs *R1CS) termToString(t compiled.Term, sbb *strings.Builder) {
 	}
 }
 
-func toHTML(l compiled.Variable, coeffs []fr.Element, MHints map[int]compiled.Hint) string {
-	var sbb strings.Builder
-	for i := 0; i < len(l.LinExp); i++ {
-		termToHTML(l.LinExp[i], &sbb, coeffs, MHints, false)
-		if i+1 < len(l.LinExp) {
-			sbb.WriteString(" + ")
-		}
-	}
-	return sbb.String()
-}
-
-func termToHTML(t compiled.Term, sbb *strings.Builder, coeffs []fr.Element, MHints map[int]compiled.Hint, offset bool) {
-	tID := t.CoeffID()
-	if tID == compiled.CoeffIdOne {
-		// do nothing, just print the variable
-	} else if tID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		sbb.WriteString("<span class=\"coefficient\">-</span>")
-	} else if tID == compiled.CoeffIdZero {
-		sbb.WriteString("<span class=\"coefficient\">0</span>")
-		return
-	} else {
-		sbb.WriteString("<span class=\"coefficient\">")
-		sbb.WriteString(coeffs[tID].String())
-		sbb.WriteString("</span>*")
-	}
-
-	vID := t.WireID()
-	class := ""
-	switch t.VariableVisibility() {
-	case schema.Internal:
-		class = "internal"
-		if _, ok := MHints[vID]; ok {
-			class = "hint"
-		}
-	case schema.Public:
-		class = "public"
-	case schema.Secret:
-		class = "secret"
-	case schema.Virtual:
-		class = "virtual"
-	case schema.Unset:
-		class = "unset"
-	default:
-		panic("not implemented")
-	}
-	if offset {
-		vID++ // for sparse R1CS, we offset to have same variable numbers as in R1CS
-	}
-	sbb.WriteString(fmt.Sprintf("<span class=\"%s\">v%d</span>", class, vID))
-
-}
-
 // GetNbCoefficients return the number of unique coefficients needed in the R1CS
 func (cs *R1CS) GetNbCoefficients() int {
 	return len(cs.Coefficients)
diff --git a/internal/backend/bw6-761/cs/r1cs_sparse.go b/internal/backend/bw6-761/cs/r1cs_sparse.go
index 4ede062b48..aa551a2e38 100644
--- a/internal/backend/bw6-761/cs/r1cs_sparse.go
+++ b/internal/backend/bw6-761/cs/r1cs_sparse.go
@@ -24,7 +24,6 @@ import (
 	"math/big"
 	"os"
 	"strings"
-	"text/template"
 
 	"github.com/consensys/gnark/backend"
 	"github.com/consensys/gnark/backend/witness"
@@ -110,11 +109,11 @@ func (cs *SparseR1CS) Solve(witness []fr.Element, opt backend.ProverConfig) ([]f
 			return solution.values, fmt.Errorf("constraint %d: %w", i, err)
 		}
 		if err := cs.checkConstraint(cs.Constraints[i], &solution); err != nil {
+			errMsg := err.Error()
 			if dID, ok := cs.MDebug[i]; ok {
-				debugInfoStr := solution.logValue(cs.DebugInfo[dID])
-				return solution.values, fmt.Errorf("%w: %s", ErrUnsatisfiedConstraint, debugInfoStr)
+				errMsg = solution.logValue(cs.DebugInfo[dID])
 			}
-			return solution.values, ErrUnsatisfiedConstraint
+			return solution.values, fmt.Errorf("constraint #%d is not satisfied: %s", i, errMsg)
 		}
 	}
 
@@ -255,37 +254,81 @@ func (cs *SparseR1CS) IsSolved(witness *witness.Witness, opts ...backend.ProverO
 	return err
 }
 
+// GetConstraints return a list of constraint formatted as in the paper
+// https://eprint.iacr.org/2019/953.pdf section 6 such that
+// qL⋅xa + qR⋅xb + qO⋅xc + qM⋅(xaxb) + qC == 0
+// each constraint is thus decomposed in [5]string with
+// 		[0] = qL⋅xa
+//		[1] = qR⋅xb
+//		[2] = qO⋅xc
+//		[3] = qM⋅(xaxb)
+//		[4] = qC
 func (cs *SparseR1CS) GetConstraints() [][]string {
-	var r [][]string
+	r := make([][]string, 0, len(cs.Constraints))
 	for _, c := range cs.Constraints {
-		// if we are worried about perf for large cs, we could do a string builder + csv format.
-		var line [6]string
-		line[0] = cs.termToString(c.L)
-		line[1] = cs.termToString(c.R)
-		line[2] = cs.termToString(c.M[0])
-		line[3] = cs.termToString(c.M[1])
-		line[4] = cs.termToString(c.O)
-		line[5] = cs.Coefficients[c.K].String()
-		r = append(r, line[:])
+		fc := cs.formatConstraint(c)
+		r = append(r, fc[:])
 	}
 	return r
 }
 
-func (cs *SparseR1CS) termToString(t compiled.Term) string {
+// r[0] = qL⋅xa
+// r[1] = qR⋅xb
+// r[2] = qO⋅xc
+// r[3] = qM⋅(xaxb)
+// r[4] = qC
+func (cs *SparseR1CS) formatConstraint(c compiled.SparseR1C) (r [5]string) {
+	isZeroM := (c.M[0].CoeffID() == compiled.CoeffIdZero) && (c.M[1].CoeffID() == compiled.CoeffIdZero)
+
 	var sbb strings.Builder
-	tID := t.CoeffID()
-	if tID == compiled.CoeffIdOne {
-		// do nothing, just print the variable
-	} else if tID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		sbb.WriteByte('-')
-	} else if tID == compiled.CoeffIdZero {
-		sbb.WriteByte('0')
-		return sbb.String()
+	cs.termToString(c.L, &sbb, false)
+	r[0] = sbb.String()
+
+	sbb.Reset()
+	cs.termToString(c.R, &sbb, false)
+	r[1] = sbb.String()
+
+	sbb.Reset()
+	cs.termToString(c.O, &sbb, false)
+	r[2] = sbb.String()
+
+	if isZeroM {
+		r[3] = "0"
 	} else {
-		sbb.WriteString(cs.Coefficients[tID].String())
-		sbb.WriteByte('*')
+		sbb.Reset()
+		sbb.WriteString(cs.Coefficients[c.M[0].CoeffID()].String())
+		sbb.WriteString("⋅")
+		sbb.WriteByte('(')
+		cs.termToString(c.M[0], &sbb, true)
+		sbb.WriteString(" × ")
+		cs.termToString(c.M[1], &sbb, true)
+		sbb.WriteByte(')')
+		r[3] = sbb.String()
+	}
+
+	r[4] = cs.Coefficients[c.K].String()
+
+	return
+}
+
+func (cs *SparseR1CS) termToString(t compiled.Term, sbb *strings.Builder, vOnly bool) {
+	if !vOnly {
+		tID := t.CoeffID()
+		if tID == compiled.CoeffIdOne {
+			// do nothing, just print the variable
+			sbb.WriteString("1")
+		} else if tID == compiled.CoeffIdMinusOne {
+			// print neg sign
+			sbb.WriteString("-1")
+		} else if tID == compiled.CoeffIdZero {
+			sbb.WriteByte('0')
+			return
+		} else {
+			sbb.WriteString(cs.Coefficients[tID].String())
+		}
+		sbb.WriteString("⋅")
 	}
+
 	vID := t.WireID()
 	visibility := t.VariableVisibility()
 
@@ -303,7 +346,6 @@ func (cs *SparseR1CS) termToString(t compiled.Term) string {
 	default:
 		sbb.WriteString("<?>")
 	}
-	return sbb.String()
 }
 
 // checkConstraint verifies that the constraint holds
@@ -318,12 +360,12 @@ func (cs *SparseR1CS) checkConstraint(c compiled.SparseR1C, solution *solution)
 	var t fr.Element
 	t.Mul(&m0, &m1).Add(&t, &l).Add(&t, &r).Add(&t, &o).Add(&t, &cs.Coefficients[c.K])
 	if !t.IsZero() {
-		return fmt.Errorf("%w\n%s + %s + (%s * %s) + %s + %s != 0", ErrUnsatisfiedConstraint,
+		return fmt.Errorf("qL⋅xa + qR⋅xb + qO⋅xc + qM⋅(xaxb) + qC != 0 → %s + %s + %s + (%s × %s) + %s != 0",
 			l.String(),
 			r.String(),
+			o.String(),
 			m0.String(),
 			m1.String(),
-			o.String(),
 			cs.Coefficients[c.K].String(),
 		)
 	}
@@ -331,39 +373,6 @@ func (cs *SparseR1CS) checkConstraint(c compiled.SparseR1C, solution *solution)
 
 }
 
-// ToHTML returns an HTML human-readable representation of the constraint system
-func (cs *SparseR1CS) ToHTML(w io.Writer) error {
-	t, err := template.New("scs.html").Funcs(template.FuncMap{
-		"toHTML":      toHTMLTerm,
-		"toHTMLCoeff": toHTMLCoeff,
-		"add":         add,
-		"sub":         sub,
-	}).Parse(compiled.SparseR1CSTemplate)
-	if err != nil {
-		return err
-	}
-
-	return t.Execute(w, cs)
-}
-
-func toHTMLTerm(t compiled.Term, coeffs []fr.Element, MHints map[int]compiled.Hint) string {
-	var sbb strings.Builder
-	termToHTML(t, &sbb, coeffs, MHints, true)
-	return sbb.String()
-}
-
-func toHTMLCoeff(cID int, coeffs []fr.Element) string {
-	if cID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		return "<span class=\"coefficient\">-1</span>"
-	}
-	var sbb strings.Builder
-	sbb.WriteString("<span class=\"coefficient\">")
-	sbb.WriteString(coeffs[cID].String())
-	sbb.WriteString("</span>")
-	return sbb.String()
-}
-
 // FrSize return fr.Limbs * 8, size in byte of a fr element
 func (cs *SparseR1CS) FrSize() int {
 	return fr.Limbs * 8
diff --git a/internal/backend/bw6-761/cs/solution.go b/internal/backend/bw6-761/cs/solution.go
index 7532956d8e..ba1a4b0688 100644
--- a/internal/backend/bw6-761/cs/solution.go
+++ b/internal/backend/bw6-761/cs/solution.go
@@ -33,9 +33,6 @@ import (
 	curve "github.com/consensys/gnark-crypto/ecc/bw6-761"
 )
 
-// ErrUnsatisfiedConstraint can be generated when solving a R1CS
-var ErrUnsatisfiedConstraint = errors.New("constraint is not satisfied")
-
 // solution represents elements needed to compute
 // a solution to a R1CS or SparseR1CS
 type solution struct {
diff --git a/internal/backend/circuits/cmp.go b/internal/backend/circuits/cmp.go
index 59f19419a7..1aecdde18c 100644
--- a/internal/backend/circuits/cmp.go
+++ b/internal/backend/circuits/cmp.go
@@ -55,5 +55,5 @@ func init() {
 		},
 	}
 
-	addNewEntry("cmp", &cmpCircuit{}, good, bad, []ecc.ID{ecc.BW6_761})
+	addNewEntry("cmp", &cmpCircuit{}, good, bad, ecc.Implemented())
 }
diff --git a/internal/generator/backend/template/representations/r1cs.go.tmpl b/internal/generator/backend/template/representations/r1cs.go.tmpl
index 88ce8c351a..e8577d81ab 100644
--- a/internal/generator/backend/template/representations/r1cs.go.tmpl
+++ b/internal/generator/backend/template/representations/r1cs.go.tmpl
@@ -14,7 +14,6 @@ import (
 	"github.com/consensys/gnark/backend/witness"
 
 	"github.com/consensys/gnark-crypto/ecc"
-	"text/template"
 
 	{{ template "import_fr" . }}
 	{{ template "import_witness" . }}
@@ -101,11 +100,11 @@ func (cs *R1CS) Solve(witness, a, b, c []fr.Element, opt backend.ProverConfig) (
 		// ensure a[i] * b[i] == c[i]
 		check.Mul(&a[i], &b[i])
 		if !check.Equal(&c[i]) {
+			errMsg := fmt.Sprintf("%s ⋅ %s != %s", a[i].String(), b[i].String(), c[i].String())
 			if dID, ok := cs.MDebug[i]; ok {
-				debugInfoStr := solution.logValue(cs.DebugInfo[dID])
-				return solution.values, fmt.Errorf("%w: %s", ErrUnsatisfiedConstraint, debugInfoStr)
+				errMsg = solution.logValue(cs.DebugInfo[dID])
 			}
-			return solution.values, ErrUnsatisfiedConstraint
+			return solution.values,  fmt.Errorf("constraint #%d is not satisfied: %s", i, errMsg)
 		}
 	}
 
@@ -271,32 +270,10 @@ func (cs *R1CS) solveConstraint(r compiled.R1C, solution *solution) error {
 	return nil
 }
 
-// TODO @gbotrel clean logs and html see https://github.com/ConsenSys/gnark/issues/140
-
-// ToHTML returns an HTML human-readable representation of the constraint system
-func (cs *R1CS) ToHTML(w io.Writer) error {
-	t, err := template.New("cs.html").Funcs(template.FuncMap{
-		"toHTML": toHTML,
-		"add":    add,
-		"sub":    sub,
-	}).Parse(compiled.R1CSTemplate)
-	if err != nil {
-		return err
-	}
-
-	return t.Execute(w, cs)
-}
-
-func add(a, b int) int {
-	return a + b
-}
-
-func sub(a, b int) int {
-	return a - b
-}
-
+// GetConstraints return a list of constraint formatted as L⋅R == O
+// such that [0] -> L, [1] -> R, [2] -> O
 func (cs *R1CS) GetConstraints() [][]string {
-	var r [][]string 
+	r  := make([][]string , len(cs.Constraints))
 	for _, c := range cs.Constraints {
 		// for each constraint, we build a string representation of it's L, R and O part 
 		// if we are worried about perf for large cs, we could do a string builder + csv format.
@@ -332,7 +309,7 @@ func (cs *R1CS) termToString(t compiled.Term, sbb *strings.Builder) {
 		return
 	} else {
 		sbb.WriteString(cs.Coefficients[tID].String())
-		sbb.WriteByte('*')
+		sbb.WriteString("⋅")
 	}
 	vID := t.WireID()
 	visibility := t.VariableVisibility()
@@ -358,59 +335,6 @@ func (cs *R1CS) termToString(t compiled.Term, sbb *strings.Builder) {
 }
 
 
-func toHTML(l compiled.Variable, coeffs []fr.Element, MHints map[int]compiled.Hint) string {
-	var sbb strings.Builder
-	for i := 0; i < len(l.LinExp); i++ {
-		termToHTML(l.LinExp[i], &sbb, coeffs, MHints, false)
-		if i+1 < len(l.LinExp) {
-			sbb.WriteString(" + ")
-		}
-	}
-	return sbb.String()
-}
-
-func termToHTML(t compiled.Term, sbb *strings.Builder, coeffs []fr.Element, MHints map[int]compiled.Hint, offset bool) {
-	tID := t.CoeffID()
-	if tID == compiled.CoeffIdOne {
-		// do nothing, just print the variable
-	} else if tID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		sbb.WriteString("<span class=\"coefficient\">-</span>")
-	} else if tID == compiled.CoeffIdZero {
-		sbb.WriteString("<span class=\"coefficient\">0</span>")
-		return
-	} else {
-		sbb.WriteString("<span class=\"coefficient\">")
-		sbb.WriteString(coeffs[tID].String())
-		sbb.WriteString("</span>*")
-	}
-
-	vID := t.WireID()
-	class := ""
-	switch t.VariableVisibility() {
-	case schema.Internal:
-		class = "internal"
-		if _, ok := MHints[vID]; ok {
-			class = "hint"
-		}
-	case schema.Public:
-		class = "public"
-	case schema.Secret:
-		class = "secret"
-	case schema.Virtual:
-		class = "virtual"
-	case schema.Unset:
-		class = "unset"
-	default:
-		panic("not implemented")
-	}
-	if offset {
-		vID++ // for sparse R1CS, we offset to have same variable numbers as in R1CS
-	}
-	sbb.WriteString(fmt.Sprintf("<span class=\"%s\">v%d</span>", class, vID))
-
-}
-
 // GetNbCoefficients return the number of unique coefficients needed in the R1CS
 func (cs *R1CS) GetNbCoefficients() int {
 	return len(cs.Coefficients)
diff --git a/internal/generator/backend/template/representations/r1cs.sparse.go.tmpl b/internal/generator/backend/template/representations/r1cs.sparse.go.tmpl
index 50d5e488c4..e423b6e8e8 100644
--- a/internal/generator/backend/template/representations/r1cs.sparse.go.tmpl
+++ b/internal/generator/backend/template/representations/r1cs.sparse.go.tmpl
@@ -5,7 +5,6 @@ import (
 	"github.com/fxamacker/cbor/v2"
 	"github.com/consensys/gnark-crypto/ecc"
 	"strings"
-	"text/template"
 	"os"
 	
 	"github.com/consensys/gnark/internal/backend/ioutils"
@@ -97,11 +96,11 @@ func (cs *SparseR1CS) Solve(witness []fr.Element, opt backend.ProverConfig) ([]f
 			return solution.values, fmt.Errorf("constraint %d: %w", i, err)
 		}
 		if err := cs.checkConstraint(cs.Constraints[i], &solution); err != nil {
+			errMsg := err.Error()
 			if dID, ok := cs.MDebug[i]; ok {
-				debugInfoStr := solution.logValue(cs.DebugInfo[dID])
-				return solution.values,  fmt.Errorf("%w: %s", ErrUnsatisfiedConstraint, debugInfoStr)
+				errMsg = solution.logValue(cs.DebugInfo[dID])
 			}
-			return solution.values, ErrUnsatisfiedConstraint
+			return solution.values,  fmt.Errorf("constraint #%d is not satisfied: %s", i, errMsg)
 		}
 	}
 
@@ -245,38 +244,82 @@ func (cs *SparseR1CS) IsSolved(witness *witness.Witness, opts ...backend.ProverO
 	return err
 }
 
+// GetConstraints return a list of constraint formatted as in the paper
+// https://eprint.iacr.org/2019/953.pdf section 6 such that
+// qL⋅xa + qR⋅xb + qO⋅xc + qM⋅(xaxb) + qC == 0
+// each constraint is thus decomposed in [5]string with
+// 		[0] = qL⋅xa
+//		[1] = qR⋅xb
+//		[2] = qO⋅xc
+//		[3] = qM⋅(xaxb)
+//		[4] = qC
 func (cs *SparseR1CS) GetConstraints() [][]string {
-	var r [][]string 
+	r := make([][]string , 0, len(cs.Constraints))
 	for _, c := range cs.Constraints {
-		// if we are worried about perf for large cs, we could do a string builder + csv format.
-		var line [6]string
-		line[0] = cs.termToString(c.L)
-		line[1] = cs.termToString(c.R)
-		line[2] = cs.termToString(c.M[0])
-		line[3] = cs.termToString(c.M[1])
-		line[4] = cs.termToString(c.O)
-		line[5] = cs.Coefficients[c.K].String()
-		r = append(r, line[:])
+		fc := cs.formatConstraint(c)
+		r = append(r, fc[:])
 	}
 	return r
 }
 
+// r[0] = qL⋅xa
+// r[1] = qR⋅xb
+// r[2] = qO⋅xc
+// r[3] = qM⋅(xaxb)
+// r[4] = qC
+func (cs *SparseR1CS) formatConstraint(c compiled.SparseR1C) (r [5]string) {
+	isZeroM :=  (c.M[0].CoeffID() == compiled.CoeffIdZero) && (c.M[1].CoeffID() == compiled.CoeffIdZero)
 
-func (cs *SparseR1CS) termToString(t compiled.Term) string  {
 	var sbb strings.Builder
-	tID := t.CoeffID()
-	if tID == compiled.CoeffIdOne {
-		// do nothing, just print the variable
-	} else if tID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		sbb.WriteByte('-')
-	} else if tID == compiled.CoeffIdZero {
-		sbb.WriteByte('0')
-		return sbb.String()
+	cs.termToString(c.L, &sbb, false)
+	r[0] = sbb.String()
+
+	sbb.Reset()
+	cs.termToString(c.R, &sbb, false)
+	r[1] = sbb.String()
+
+	sbb.Reset()
+	cs.termToString(c.O, &sbb, false)
+	r[2] = sbb.String()
+
+	if isZeroM {
+		r[3] = "0"
 	} else {
-		sbb.WriteString(cs.Coefficients[tID].String())
-		sbb.WriteByte('*')
+		sbb.Reset()
+		sbb.WriteString(cs.Coefficients[c.M[0].CoeffID()].String())
+		sbb.WriteString("⋅")
+		sbb.WriteByte('(')
+		cs.termToString(c.M[0], &sbb, true)
+		sbb.WriteString(" × ")
+		cs.termToString(c.M[1], &sbb, true)
+		sbb.WriteByte(')')
+		r[3] = sbb.String()
 	}
+
+	r[4] = cs.Coefficients[c.K].String()
+
+	return 
+}
+
+
+func (cs *SparseR1CS) termToString(t compiled.Term, sbb *strings.Builder, vOnly bool)   {
+	if !vOnly {
+		tID := t.CoeffID()
+		if tID == compiled.CoeffIdOne {
+			// do nothing, just print the variable
+			sbb.WriteString("1")
+		} else if tID == compiled.CoeffIdMinusOne {
+			// print neg sign
+			sbb.WriteString("-1")
+		} else if tID == compiled.CoeffIdZero {
+			sbb.WriteByte('0')
+			return
+		} else {
+			sbb.WriteString(cs.Coefficients[tID].String())
+		}
+		sbb.WriteString("⋅")
+	}
+
 	vID := t.WireID()
 	visibility := t.VariableVisibility()
 
@@ -294,7 +337,6 @@ func (cs *SparseR1CS) termToString(t compiled.Term) string  {
 	default:
 		sbb.WriteString("<?>")
 	}
-	return sbb.String()
 }
 
 
@@ -311,54 +353,19 @@ func (cs *SparseR1CS) checkConstraint(c compiled.SparseR1C, solution *solution)
 	var t fr.Element 
 	t.Mul(&m0, &m1).Add(&t, &l).Add(&t, &r).Add(&t, &o).Add(&t, &cs.Coefficients[c.K])
 	if !t.IsZero() {
-		return fmt.Errorf("%w\n%s + %s + (%s * %s) + %s + %s != 0",ErrUnsatisfiedConstraint, 
-		l.String(),
-		r.String(),
-		m0.String(),
-		m1.String(),
-		o.String(),
-		cs.Coefficients[c.K].String(),
+		return fmt.Errorf("qL⋅xa + qR⋅xb + qO⋅xc + qM⋅(xaxb) + qC != 0 → %s + %s + %s + (%s × %s) + %s != 0",
+			l.String(),
+			r.String(),
+			o.String(),
+			m0.String(),
+			m1.String(),
+			cs.Coefficients[c.K].String(),
 		)
 	}
 	return nil 
 
 }
 
-
-// ToHTML returns an HTML human-readable representation of the constraint system
-func (cs *SparseR1CS) ToHTML(w io.Writer) error {
-	t, err := template.New("scs.html").Funcs(template.FuncMap{
-		"toHTML": toHTMLTerm,
-		"toHTMLCoeff": toHTMLCoeff,
-		"add": add,
-		"sub": sub,
-	}).Parse(compiled.SparseR1CSTemplate)
-	if err != nil {
-		return err
-	}
-
-	return t.Execute(w, cs)
-}
-
-
-func toHTMLTerm(t compiled.Term, coeffs []fr.Element, MHints map[int]compiled.Hint) string {
-	var sbb strings.Builder
-	termToHTML(t, &sbb, coeffs, MHints, true)
-	return sbb.String()
-}
-
-func toHTMLCoeff(cID int, coeffs []fr.Element) string {
-	if cID == compiled.CoeffIdMinusOne {
-		// print neg sign
-		return "<span class=\"coefficient\">-1</span>"
-	}
-	var sbb strings.Builder 
-	sbb.WriteString("<span class=\"coefficient\">")
-	sbb.WriteString(coeffs[cID].String())
-	sbb.WriteString("</span>")
-	return sbb.String()
-}
-
 // FrSize return fr.Limbs * 8, size in byte of a fr element
 func (cs *SparseR1CS) FrSize() int {
 	return fr.Limbs * 8
diff --git a/internal/generator/backend/template/representations/solution.go.tmpl b/internal/generator/backend/template/representations/solution.go.tmpl
index 88ba32f0c5..ab64434800 100644
--- a/internal/generator/backend/template/representations/solution.go.tmpl
+++ b/internal/generator/backend/template/representations/solution.go.tmpl
@@ -14,9 +14,6 @@ import (
 	{{ template "import_curve" . }}
 )
 
-// ErrUnsatisfiedConstraint can be generated when solving a R1CS
-var ErrUnsatisfiedConstraint = errors.New("constraint is not satisfied")
-
 // solution represents elements needed to compute
 // a solution to a R1CS or SparseR1CS
 type solution struct {