diff --git a/src/cli.zig b/src/cli.zig
index 3174936..f54ce5d 100644
--- a/src/cli.zig
+++ b/src/cli.zig
@@ -4,6 +4,7 @@ const std = @import("std");
 const cova = @import("cova");
 const assets = @import("assets.zig");
 
+const Speed = main.Speed;
 const Color = main.Color;
 const Style = main.Style;
 const Mode = main.Mode;
@@ -69,6 +70,7 @@ pub const CommandT = cova.Command.Custom(.{
     },
     .val_config = .{
         .custom_types = &.{
+            Speed,
             Color,
             Style,
             Mode,
@@ -133,6 +135,16 @@ pub const setup_cmd: CommandT = .{
                 .default_val = 0,
             }),
         },
+        .{
+            .name = "speed",
+            .description = "Set speed (fast, slow).",
+            .long_name = "speed",
+            .val = ValueT.ofType(Speed, .{
+                .name = "speed_val",
+                .default_val = Speed.fast,
+                .alias_child_type = "string",
+            }),
+        },
         .{
             .name = "version",
             .description = "Show the 'xtxf' version.",
diff --git a/src/main.zig b/src/main.zig
index a4cd168..12dccdb 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -23,7 +23,8 @@ const VERSION = if (build_opt.gxt.dirty == null) HEAD_HASH ++ "-unverified" else
 
 const FRAME = 39730492;
 
-pub const Mode = enum(u8) { binary, decimal, hexadecimal, textual };
+pub const Speed = enum { slow, fast };
+pub const Mode = enum { binary, decimal, hexadecimal, textual };
 pub const Style = enum { default, columns, crypto, grid, blocks };
 pub const Color = enum(u32) { default = tb.TB_DEFAULT, red = tb.TB_RED, green = tb.TB_GREEN, blue = tb.TB_BLUE, yellow = tb.TB_YELLOW, magenta = tb.TB_MAGENTA };
 
@@ -135,6 +136,7 @@ const Core = struct {
 const Handler = struct {
     mutex: Mutex = Mutex{},
     halt: bool = true,
+    speed: Speed = .fast,
     duration: u32 = 0,
     pause: bool = false,
     mode: Mode = Mode.binary,
@@ -250,7 +252,10 @@ fn printCells(core: *Core, handler: *Handler, rand: std.rand.Random) !void {
 
         _ = tb.tb_present();
         core.setRendering(false);
-        std.time.sleep(FRAME);
+        std.time.sleep(switch (handler.speed) {
+            .slow => FRAME * 2,
+            .fast => FRAME,
+        });
     }
 }
 
@@ -327,6 +332,10 @@ pub fn main() !void {
         handler.duration = try time.val.getAs(u32);
     }
 
+    if (opts.get("speed")) |speed| {
+        handler.speed = try speed.val.getAs(Speed);
+    }
+
     if (opts.get("pulse")) |pulse| {
         core.pulse = try pulse.val.getAs(bool);
     }
diff --git a/test/cli.zig b/test/cli.zig
index 1ec6db0..5885f3b 100644
--- a/test/cli.zig
+++ b/test/cli.zig
@@ -22,6 +22,13 @@ test "default" {
     try std.testing.expectEqual(term, std.process.Child.Term{ .Exited = 0 });
 }
 
+test "speed" {
+    const argv = [_][]const u8{ exe_path, "--time=1", "-s=default", "--speed=slow" };
+    const term = try runner(argv);
+
+    try std.testing.expectEqual(term, std.process.Child.Term{ .Exited = 0 });
+}
+
 test "mode: decimal" {
     const argv = [_][]const u8{ exe_path, "--time=1", "-m=decimal" };
     const term = try runner(argv);