Sync additional docs and metadata

exercises/practice/all-your-base/.docs/instructions.md

@@ -1,37 +1,27 @@
 # Instructions
 
-Convert a number, represented as a sequence of digits in one base, to any other base.
+Convert a sequence of digits in one base, representing a number, into a sequence of digits in another base, representing the same number.
 
-Implement general base conversion.
-Given a number in base **a**, represented as a sequence of digits, convert it to base **b**.
+~~~~exercism/note
+Try to implement the conversion yourself.
+Do not use something else to perform the conversion for you.
+~~~~
 
-## Note
-
-- Try to implement the conversion yourself.
-  Do not use something else to perform the conversion for you.
-
-## About [Positional Notation][positional-notation]
 ## About [Positional Notation][positional-notation]
 
-In positional notation, a number in base **b** can be understood as a linear combination of powers of **b**.
 In positional notation, a number in base **b** can be understood as a linear combination of powers of **b**.
 
-The number 42, _in base 10_, means:
 The number 42, _in base 10_, means:
 
-`(4 * 10^1) + (2 * 10^0)`
+`(4 × 10¹) + (2 × 10⁰)`
 
-The number 101010, _in base 2_, means:
 The number 101010, _in base 2_, means:
 
-`(1 * 2^5) + (0 * 2^4) + (1 * 2^3) + (0 * 2^2) + (1 * 2^1) + (0 * 2^0)`
+`(1 × 2⁵) + (0 × 2⁴) + (1 × 2³) + (0 × 2²) + (1 × 2¹) + (0 × 2⁰)`
 
-The number 1120, _in base 3_, means:
 The number 1120, _in base 3_, means:
 
-`(1 * 3^3) + (1 * 3^2) + (2 * 3^1) + (0 * 3^0)`
-
-_Yes. Those three numbers above are exactly the same. Congratulations!_
+`(1 × 3³) + (1 × 3²) + (2 × 3¹) + (0 × 3⁰)`
 
 _Yes. Those three numbers above are exactly the same. Congratulations!_
 

exercises/practice/anagram/.docs/instructions.md

@@ -1,9 +1,9 @@
 # Instructions
 
-An anagram is a rearrangement of letters to form a new word: for example `"owns"` is an anagram of `"snow"`.
-A word is not its own anagram: for example, `"stop"` is not an anagram of `"stop"`.
+Your task is to, given a target word and a set of candidate words, to find the subset of the candidates that are anagrams of the target.
 
-Given a target word and a set of candidate words, this exercise requests the anagram set: the subset of the candidates that are anagrams of the target.
+An anagram is a rearrangement of letters to form a new word: for example `"owns"` is an anagram of `"snow"`.
+A word is _not_ its own anagram: for example, `"stop"` is not an anagram of `"stop"`.
 
 The target and candidates are words of one or more ASCII alphabetic characters (`A`-`Z` and `a`-`z`).
 Lowercase and uppercase characters are equivalent: for example, `"PoTS"` is an anagram of `"sTOp"`, but `StoP` is not an anagram of `sTOp`.

exercises/practice/bank-account/.docs/instructions.md

@@ -1,12 +1,10 @@
 # Instructions
 
-Simulate a bank account supporting opening/closing, withdrawals, and deposits of money.
-Watch out for concurrent transactions!
+Your task is to implement bank accounts supporting opening/closing, withdrawals, and deposits of money.
 
-A bank account can be accessed in multiple ways.
-Clients can make deposits and withdrawals using the internet, mobile phones, etc.
-Shops can charge against the account.
-
-Create an account that can be accessed from multiple threads/processes (terminology depends on your programming language).
+As bank accounts can be accessed in many different ways (internet, mobile phones, automatic charges), your bank software must allow accounts to be safely accessed from multiple threads/processes (terminology depends on your programming language) in parallel.
+For example, there may be many deposits and withdrawals occurring in parallel; you need to ensure there are no [race conditions][wikipedia] between when you read the account balance and set the new balance.
 
 It should be possible to close an account; operations against a closed account must fail.
+
+[wikipedia]: https://en.wikipedia.org/wiki/Race_condition#In_software

exercises/practice/flatten-array/.docs/instructions.md

@@ -2,7 +2,7 @@
 
 Take a nested list and return a single flattened list with all values except nil/null.
 
-The challenge is to write a function that accepts an arbitrarily-deep nested list-like structure and returns a flattened structure without any nil/null values.
+The challenge is to take an arbitrarily-deep nested list-like structure and produce a flattened structure without any nil/null values.
 
 For example:
 

exercises/practice/go-counting/.docs/instructions.md

@@ -5,10 +5,10 @@ Count the scored points on a Go board.
 In the game of go (also known as baduk, igo, cờ vây and wéiqí) points are gained by completely encircling empty intersections with your stones.
 The encircled intersections of a player are known as its territory.
 
-Write a function that determines the territory of each player.
+Calculate the territory of each player.
 You may assume that any stones that have been stranded in enemy territory have already been taken off the board.
 
-Write a function that determines the territory which includes a specified coordinate.
+Determine the territory which includes a specified coordinate.
 
 Multiple empty intersections may be encircled at once and for encircling only horizontal and vertical neighbors count.
 In the following diagram the stones which matter are marked "O" and the stones that don't are marked "I" (ignored).
@@ -25,7 +25,7 @@ Empty spaces represent empty intersections.
 
 To be more precise an empty intersection is part of a player's territory if all of its neighbors are either stones of that player or empty intersections that are part of that player's territory.
 
-For more information see [wikipedia][go-wikipedia] or [Sensei's Library][go-sensei].
+For more information see [Wikipedia][go-wikipedia] or [Sensei's Library][go-sensei].
 
 [go-wikipedia]: https://en.wikipedia.org/wiki/Go_%28game%29
 [go-sensei]: https://senseis.xmp.net/

exercises/practice/hamming/.docs/instructions.md

@@ -1,6 +1,6 @@
 # Instructions
 
-Calculate the Hamming Distance between two DNA strands.
+Calculate the Hamming distance between two DNA strands.
 
 Your body is made up of cells that contain DNA.
 Those cells regularly wear out and need replacing, which they achieve by dividing into daughter cells.
@@ -9,18 +9,18 @@ In fact, the average human body experiences about 10 quadrillion cell divisions
 When cells divide, their DNA replicates too.
 Sometimes during this process mistakes happen and single pieces of DNA get encoded with the incorrect information.
 If we compare two strands of DNA and count the differences between them we can see how many mistakes occurred.
-This is known as the "Hamming Distance".
+This is known as the "Hamming distance".
 
-We read DNA using the letters C,A,G and T.
+We read DNA using the letters C, A, G and T.
 Two strands might look like this:
 
     GAGCCTACTAACGGGAT
     CATCGTAATGACGGCCT
     ^ ^ ^  ^ ^    ^^
 
-They have 7 differences, and therefore the Hamming Distance is 7.
+They have 7 differences, and therefore the Hamming distance is 7.
 
-The Hamming Distance is useful for lots of things in science, not just biology, so it's a nice phrase to be familiar with :)
+The Hamming distance is useful for lots of things in science, not just biology, so it's a nice phrase to be familiar with :)
 
 ## Implementation notes
 

exercises/practice/kindergarten-garden/.docs/instructions.md

@@ -2,29 +2,28 @@
 
 Your task is to, given a diagram, determine which plants each child in the kindergarten class is responsible for.
 
-The kindergarten class is learning about growing plants.
-The teacher thought it would be a good idea to give them actual seeds, plant them in actual dirt, and grow actual plants.
+There are 12 children in the class:
+
+- Alice, Bob, Charlie, David, Eve, Fred, Ginny, Harriet, Ileana, Joseph, Kincaid, and Larry.
+
+Four different types of seeds are planted:
 
-They've chosen to grow grass, clover, radishes, and violets.
+| Plant  | Diagram encoding |
+| ------ | ---------------- |
+| Grass  | G                |
+| Clover | C                |
+| Radish | R                |
+| Violet | V                |
 
-To this end, the children have put little cups along the window sills, and
-planted one type of plant in each cup, choosing randomly from the available
-types of seeds.
+Each child gets four cups, two on each row:
 
 ```text
 [window][window][window]
 ........................ # each dot represents a cup
 ........................
 ```
 
-There are 12 children in the class:
-
-- Alice, Bob, Charlie, David,
-- Eve, Fred, Ginny, Harriet,
-- Ileana, Joseph, Kincaid, and Larry.
-
-Each child gets 4 cups, two on each row.
-Their teacher assigns cups to the children alphabetically by their names.
+Their teacher assigns cups to the children alphabetically by their names, which means that Alice comes first and Larry comes last.
 
 Here is an example diagram representing Alice's plants:
 
@@ -34,13 +33,9 @@ VR......................
 RG......................
 ```
 
-In the first row, nearest the windows, she has a violet and a radish.
-In the second row she has a radish and some grass.
 In the first row, nearest the windows, she has a violet and a radish.
 In the second row she has a radish and some grass.
 
-Your program will be given the plants from left-to-right starting with the row nearest the windows.
-From this, it should be able to determine which plants belong to each student.
 Your program will be given the plants from left-to-right starting with the row nearest the windows.
 From this, it should be able to determine which plants belong to each student.
 

exercises/practice/luhn/.docs/instructions.md

@@ -22,7 +22,8 @@ The first step of the Luhn algorithm is to double every second digit, starting f
 We will be doubling
 
 ```text
-4_3_ 3_9_ 0_4_ 6_6_
+4539 3195 0343 6467
+↑ ↑  ↑ ↑  ↑ ↑  ↑ ↑  (double these)
 ```
 
 If doubling the number results in a number greater than 9 then subtract 9 from the product.

exercises/practice/matching-brackets/.docs/instructions.md

@@ -1,4 +1,5 @@
 # Instructions
 
 Given a string containing brackets `[]`, braces `{}`, parentheses `()`, or any combination thereof, verify that any and all pairs are matched and nested correctly.
-The string may also contain other characters, which for the purposes of this exercise should be ignored.
+Any other characters should be ignored.
+For example, `"{what is (42)}?"` is balanced and `"[text}"` is not.

exercises/practice/matching-brackets/.docs/introduction.md

@@ -0,0 +1,8 @@
+# Introduction
+
+You're given the opportunity to write software for the Bracketeer™, an ancient but powerful mainframe.
+The software that runs on it is written in a proprietary language.
+Much of its syntax is familiar, but you notice _lots_ of brackets, braces and parentheses.
+Despite the Bracketeer™ being powerful, it lacks flexibility.
+If the source code has any unbalanced brackets, braces or parentheses, the Bracketeer™ crashes and must be rebooted.
+To avoid such a scenario, you start writing code that can verify that brackets, braces, and parentheses are balanced before attempting to run it on the Bracketeer™.

exercises/practice/meetup/.docs/instructions.md

@@ -1,41 +1,24 @@
 # Instructions
 
-Recurring monthly meetups are generally scheduled on the given weekday of a given week each month.
-In this exercise you will be given the recurring schedule, along with a month and year, and then asked to find the exact date of the meetup.
+Your task is to find the exact date of a meetup, given a month, year, weekday and week.
 
-For example a meetup might be scheduled on the _first Monday_ of every month.
-You might then be asked to find the date that this meetup will happen in January 2018.
-In other words, you need to determine the date of the first Monday of January 2018.
+There are five week values to consider: `first`, `second`, `third`, `fourth`, `last`, `teenth`.
+
+For example, you might be asked to find the date for the meetup on the first Monday in January 2018 (January 1, 2018).
 
 Similarly, you might be asked to find:
 
 - the third Tuesday of August 2019 (August 20, 2019)
 - the teenth Wednesday of May 2020 (May 13, 2020)
 - the fourth Sunday of July 2021 (July 25, 2021)
 - the last Thursday of November 2022 (November 24, 2022)
+- the teenth Saturday of August 1953 (August 15, 1953)
 
-The descriptors you are expected to process are: `first`, `second`, `third`, `fourth`, `last`, `teenth`.
-
-Note that descriptor `teenth` is a made-up word.
-
-It refers to the seven numbers that end in '-teen' in English: 13, 14, 15, 16, 17, 18, and 19.
-But general descriptions of dates use ordinal numbers, e.g. the _first_ Monday, the _third_ Tuesday.
-
-For the numbers ending in '-teen', that becomes:
-
-- 13th (thirteenth)
-- 14th (fourteenth)
-- 15th (fifteenth)
-- 16th (sixteenth)
-- 17th (seventeenth)
-- 18th (eighteenth)
-- 19th (nineteenth)
+## Teenth
 
-So there are seven numbers ending in '-teen'.
-And there are also seven weekdays (Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday).
-Therefore, it is guaranteed that each day of the week (Monday, Tuesday, ...) will have exactly one numbered day ending with "teen" each month.
+The teenth week refers to the seven days in a month that end in '-teenth' (13th, 14th, 15th, 16th, 17th, 18th and 19th).
 
-If asked to find the teenth Saturday of August, 1953 (or, alternately the "Saturteenth" of August, 1953), we need to look at the calendar for August 1953:
+If asked to find the teenth Saturday of August, 1953, we check its calendar:
 
 ```plaintext
     August 1953
@@ -48,4 +31,4 @@ Su Mo Tu We Th Fr Sa
 30 31
 ```
 
-The Saturday that has a number ending in '-teen' is August 15, 1953.
+From this we find that the teenth Saturday is August 15, 1953.

exercises/practice/meetup/.meta/config.json

@@ -26,6 +26,5 @@
     ]
   },
   "blurb": "Calculate the date of meetups.",
-  "source": "Jeremy Hinegardner mentioned a Boulder meetup that happens on the Wednesteenth of every month",
-  "source_url": "http://www.copiousfreetime.org/"
+  "source": "Jeremy Hinegardner mentioned a Boulder meetup that happens on the Wednesteenth of every month"
 }

exercises/practice/minesweeper/.docs/instructions.md

@@ -1,19 +1,13 @@
 # Instructions
 
-Add the mine counts to a completed Minesweeper board.
+Your task is to add the mine counts to empty squares in a completed Minesweeper board.
+The board itself is a rectangle composed of squares that are either empty (`' '`) or a mine (`'*'`).
 
-Minesweeper is a popular game where the user has to find the mines using numeric hints that indicate how many mines are directly adjacent (horizontally, vertically, diagonally) to a square.
+For each empty square, count the number of mines adjacent to it (horizontally, vertically, diagonally).
+If the empty square has no adjacent mines, leave it empty.
+Otherwise replace it with the adjacent mines count.
 
-In this exercise you have to create some code that counts the number of mines adjacent to a given empty square and replaces that square with the count.
-
-The board is a rectangle composed of blank space (' ') characters.
-A mine is represented by an asterisk (`*`) character.
-
-If a given space has no adjacent mines at all, leave that square blank.
-
-## Examples
-
-For example you may receive a 5 x 4 board like this (empty spaces are represented here with the '·' character for display on screen):
+For example, you may receive a 5 x 4 board like this (empty spaces are represented here with the '·' character for display on screen):
 
 ```text
 ·*·*·

exercises/practice/pascals-triangle/.docs/instructions.md

@@ -1,14 +1,35 @@
 # Instructions
 
-Compute Pascal's triangle up to a given number of rows.
+Your task is to output the first N rows of Pascal's triangle.
 
-In Pascal's Triangle each number is computed by adding the numbers to the right and left of the current position in the previous row.
+[Pascal's triangle][wikipedia] is a triangular array of positive integers.
+
+In Pascal's triangle, the number of values in a row is equal to its row number (which starts at one).
+Therefore, the first row has one value, the second row has two values, and so on.
+
+The first (topmost) row has a single value: `1`.
+Subsequent rows' values are computed by adding the numbers directly to the right and left of the current position in the previous row.
+
+If the previous row does _not_ have a value to the left or right of the current position (which only happens for the leftmost and rightmost positions), treat that position's value as zero (effectively "ignoring" it in the summation).
+
+## Example
+
+Let's look at the first 5 rows of Pascal's Triangle:
 
 ```text
     1
    1 1
   1 2 1
  1 3 3 1
 1 4 6 4 1
-# ... etc
 ```
+
+The topmost row has one value, which is `1`.
+
+The leftmost and rightmost values have only one preceding position to consider, which is the position to its right respectively to its left.
+With the topmost value being `1`, it follows from this that all the leftmost and rightmost values are also `1`.
+
+The other values all have two positions to consider.
+For example, the fifth row's (`1 4 6 4 1`) middle value is `6`, as the values to its left and right in the preceding row are `3` and `3`:
+
+[wikipedia]: https://en.wikipedia.org/wiki/Pascal%27s_triangle

exercises/practice/pascals-triangle/.docs/introduction.md

@@ -0,0 +1,22 @@
+# Introduction
+
+With the weather being great, you're not looking forward to spending an hour in a classroom.
+Annoyed, you enter the class room, where you notice a strangely satisfying triangle shape on the blackboard.
+Whilst waiting for your math teacher to arrive, you can't help but notice some patterns in the triangle: the outer values are all ones, each subsequent row has one more value than its previous row and the triangle is symmetrical.
+Weird!
+
+Not long after you sit down, your teacher enters the room and explains that this triangle is the famous [Pascal's triangle][wikipedia].
+
+Over the next hour, your teacher reveals some amazing things hidden in this triangle:
+
+- It can be used to compute how many ways you can pick K elements from N values.
+- It contains the Fibonacci sequence.
+- If you color odd and even numbers differently, you get a beautiful pattern called the [Sierpiński triangle][wikipedia-sierpinski-triangle].
+
+The teacher implores you and your classmates to lookup other uses, and assures you that there are lots more!
+At that moment, the school bell rings.
+You realize that for the past hour, you were completely absorbed in learning about Pascal's triangle.
+You quickly grab your laptop from your bag and go outside, ready to enjoy both the sunshine _and_ the wonders of Pascal's triangle.
+
+[wikipedia]: https://en.wikipedia.org/wiki/Pascal%27s_triangle
+[wikipedia-sierpinski-triangle]: https://en.wikipedia.org/wiki/Sierpi%C5%84ski_triangle