The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 5 days. Why not try and solve them ahead of time?
Tutorial in all languages in bytes. Achievements Cheevos Holes Languages Medals Miscellaneous All Holes 12 Days of Christmas 24 Game 99 Bottles of Beer Abundant Numbers Abundant Numbers (Long) Arabic to Roman Arithmetic Numbers Arrows Ascending Primes ASCII Table Billiards brainfuck Calendar Card Number Validation Catalan Numbers Catalan’s Constant Christmas Trees Collatz Continued Fractions CSS Colors Cubes Day of Week DFA Simulator Diamonds Divisors Emirp Numbers Emirp Numbers (Long) Emojify Evil Numbers Evil Numbers (Long) Factorial Factorisation Farey Sequence Fibonacci Fizz Buzz Foo Fizz Buzz Bar Forsyth–Edwards Notation Fractions Game of Life Gijswijt’s Sequence Happy Numbers Happy Numbers (Long) Hexdump Hilbert Curve Intersection Inventory Sequence ISBN Jacobi Symbol Kaprekar Numbers Kolakoski Constant Kolakoski Sequence Leap Years Levenshtein Distance Leyland Numbers ln 2 Look and Say Lucky Numbers Lucky Tickets Mahjong Mandelbrot Maze Medal Tally Minesweeper Morse Decoder Morse Encoder Multitap Input Musical Chords N Queens Niven Numbers Niven Numbers (Long) Number Spiral Odious Numbers Odious Numbers (Long) Ordinal Numbers PalindromemordnilaP Pangram Grep Partition Numbers Pascal’s Triangle Pernicious Numbers Pernicious Numbers (Long) Poker Polyominoes Prime Numbers Prime Numbers (Long) Proximity Grid QR Decoder Quine Recamán Repeating Decimals Reverse Polish Notation Reversi Rijndael S-box Rock-paper-scissors-Spock-lizard Roman to Arabic ROT13 Rule 110 Scrambled Sort Set Seven Segment SI Units Sierpiński Triangle Smith Numbers Spelling Numbers Star Wars GPT Star Wars Opening Crawl Sudoku Sudoku (Fill-in) Ten-pin Bowling Tic-tac-toe Time Distance Tongue-twisters Topological Sort Tower of Hanoi Transpose Sentence Trinomial Triangle United States Vampire Numbers Van Eck Sequence Zeckendorf Representation Zodiac Signs γ λ π τ φ √2 𝑒 Alphabetic Numbers Apéry’s Constant Binary Lambda Calculus Connect Four Crossword CSS Colors (Inverse) CSS Grid Ellipse Perimeters Flags Floyd-Steinberg Dithering Gray Code Decoder Gray Code Encoder Hexagonal Spiral Highly Composite Numbers NFA Simulator Numbrix Odd Polyomino Tiling p-adic Expansion Polygon Triangulations QR Encoder Quadratic Formula Rectangle Fill Semiprime Numbers Smooth Numbers Snake Sphenic Numbers Taxicab Numbers Turtle Tutorial All Languages ><> ALGOL 68 ArkScript Assembly AWK Bash BASIC Berry brainfuck C C# C++ Civet Clojure COBOL Coconut Common Lisp Crystal D Dart Elixir Erlang F# Factor Forth Fortran Gleam Go GolfScript Groovy Haskell Hexagony J Janet Java JavaScript jq Julia K Kotlin Lua Nim OCaml Pascal Perl PHP PowerShell Prolog Python R Raku Rockstar Ruby Rust Scheme sed SQL Swift Tcl TeX V VimL Wren Zig 05AB1E APL Arturo Befunge BQN CJam CoffeeScript Egel Fennel Harbour Hare Haxe Hush Hy iogii Knight Lily Luau Odin Picat Qore Racket Rebol Rexx Scala Squirrel Stax Uiua Umka Vala Vyxal Bytes Chars Scoring Bytes Chars Language All ><> ALGOL 68 ArkScript Assembly AWK Bash BASIC Berry brainfuck C C# C++ Civet Clojure COBOL Coconut Common Lisp Crystal D Dart Elixir Erlang F# Factor Forth Fortran Gleam Go GolfScript Groovy Haskell Hexagony J Janet Java JavaScript jq Julia K Kotlin Lua Nim OCaml Pascal Perl PHP PowerShell Prolog Python R Raku Rockstar Ruby Rust Scheme sed SQL Swift Tcl TeX V VimL Wren Zig Experimental Language 05AB1E APL Arturo Befunge BQN CJam CoffeeScript Egel Fennel Harbour Hare Haxe Hush Hy iogii Knight Lily Luau Odin Picat Qore Racket Rebol Rexx Scala Squirrel Stax Uiua Umka Vala Vyxal Hole All 12 Days of Christmas 24 Game 99 Bottles of Beer Abundant Numbers Abundant Numbers (Long) Arabic to Roman Arithmetic Numbers Arrows Ascending Primes ASCII Table Billiards brainfuck Calendar Card Number Validation Catalan Numbers Catalan’s Constant Christmas Trees Collatz Continued Fractions CSS Colors Cubes Day of Week DFA Simulator Diamonds Divisors Emirp Numbers Emirp Numbers (Long) Emojify Evil Numbers Evil Numbers (Long) Factorial Factorisation Farey Sequence Fibonacci Fizz Buzz Foo Fizz Buzz Bar Forsyth–Edwards Notation Fractions Game of Life Gijswijt’s Sequence Happy Numbers Happy Numbers (Long) Hexdump Hilbert Curve Intersection Inventory Sequence ISBN Jacobi Symbol Kaprekar Numbers Kolakoski Constant Kolakoski Sequence Leap Years Levenshtein Distance Leyland Numbers ln 2 Look and Say Lucky Numbers Lucky Tickets Mahjong Mandelbrot Maze Medal Tally Minesweeper Morse Decoder Morse Encoder Multitap Input Musical Chords N Queens Niven Numbers Niven Numbers (Long) Number Spiral Odious Numbers Odious Numbers (Long) Ordinal Numbers PalindromemordnilaP Pangram Grep Partition Numbers Pascal’s Triangle Pernicious Numbers Pernicious Numbers (Long) Poker Polyominoes Prime Numbers Prime Numbers (Long) Proximity Grid QR Decoder Quine Recamán Repeating Decimals Reverse Polish Notation Reversi Rijndael S-box Rock-paper-scissors-Spock-lizard Roman to Arabic ROT13 Rule 110 Scrambled Sort Set Seven Segment SI Units Sierpiński Triangle Smith Numbers Spelling Numbers Star Wars GPT Star Wars Opening Crawl Sudoku Sudoku (Fill-in) Ten-pin Bowling Tic-tac-toe Time Distance Tongue-twisters Topological Sort Tower of Hanoi Transpose Sentence Trinomial Triangle United States Vampire Numbers Van Eck Sequence Zeckendorf Representation Zodiac Signs γ λ π τ φ √2 𝑒 Experimental Hole Alphabetic Numbers Apéry’s Constant Binary Lambda Calculus Connect Four Crossword CSS Colors (Inverse) CSS Grid Ellipse Perimeters Flags Floyd-Steinberg Dithering Gray Code Decoder Gray Code Encoder Hexagonal Spiral Highly Composite Numbers NFA Simulator Numbrix Odd Polyomino Tiling p-adic Expansion Polygon Triangulations QR Encoder Quadratic Formula Rectangle Fill Semiprime Numbers Smooth Numbers Snake Sphenic Numbers Taxicab Numbers Turtle Tutorial # Golfer Points Bytes Time Submitted 621st edsrzf 🇳🇿 0 56 7ms 19 Jul 2025 621st AbrahamJLR 🇻🇪 0 56 7ms 20 Jul 2025 621st albanian-laundromat 0 56 534ms 4 Aug 2025 621st snoozingnewt 🇨🇦 0 56 2ms 15 Sep 2025 621st snoozingnewt 🇨🇦 0 56 7ms 15 Sep 2025 621st CaedenHarper 🇨🇦 0 56 2ms 1 Oct 2025 621st GolfingSuccess 🇬🇷 0 56 2ms 12 Nov 2025 621st edsrzf 🇳🇿 0 56 2ms 12 Nov 2025 621st JOrE20 0 56 7ms 26 Nov 2025 621st HumanoidCPU 0 56 7ms 1 Jan 2026 651st edsrzf 🇳🇿 0 57 9ms 8 Feb 2025 651st emgordon154 0 57 4ms 14 Mar 2025 651st Yewzir 🇧🇪 0 57 2ms 16 Mar 2025 651st Natanaelel 🇸🇪 0 57 2ms 20 Dec 2025 651st error256 0 57 82ms 1 Feb 2026 656th kg583 🇺🇸 0 58 6ms 21 Nov 2024 656th ovs-code 🇩🇪 0 58 6ms 25 Nov 2024 656th GolfingSuccess 🇬🇷 0 58 6ms 25 Nov 2024 656th GolfingSuccess 🇬🇷 0 58 3ms 25 Nov 2024 656th AlephSquirrel 0 58 6ms 25 Nov 2024 656th emgordon154 0 58 3ms 26 Nov 2024 656th m-tkach 🇺🇦 0 58 3ms 26 Nov 2024 656th emgordon154 0 58 6ms 27 Nov 2024 656th Shanethegamer 🇺🇸 0 58 3ms 10 Dec 2024 656th MeWhenI 🇻🇦 0 58 3ms 11 Dec 2024 656th Shanethegamer 🇺🇸 0 58 6ms 17 Dec 2024 656th zacjl 0 58 6ms 31 Dec 2024 656th CaedenHarper 🇨🇦 0 58 3ms 4 Jan 2025 656th CLOStrophobic 🇮🇹 0 58 6ms 17 Jan 2025 656th voytxt 🇨🇿 0 58 3ms 25 Jan 2025 656th sisyphus-ppcg 🇦🇺 0 58 3ms 28 Jan 2025 656th UnderKoen 🇳🇱 0 58 4ms 28 Jan 2025 656th dokutan 0 58 570ms 3 Feb 2025 656th HumanoidCPU 0 58 3ms 4 Feb 2025 656th emgordon154 0 58 8ms 5 Feb 2025 656th edsrzf 🇳🇿 0 58 5ms 9 Feb 2025 656th targrik 0 58 3ms 15 Feb 2025 656th edsrzf 🇳🇿 0 58 3ms 19 Feb 2025 656th orthoplex 🇨🇽 0 58 4ms 16 Apr 2025 656th edsrzf 🇳🇿 0 58 4ms 17 Apr 2025 656th DialFrost 🇸🇬 0 58 6ms 17 Apr 2025 656th DialFrost 🇸🇬 0 58 4ms 17 Apr 2025 656th Shanethegamer 🇺🇸 0 58 4ms 17 Apr 2025 656th DialFrost 🇸🇬 0 58 4ms 17 Apr 2025 656th GolfingSuccess 🇬🇷 0 58 4ms 17 Apr 2025 656th HumanoidCPU 0 58 6ms 18 Apr 2025 656th HumanoidCPU 0 58 4ms 18 Apr 2025 656th CaedenHarper 🇨🇦 0 58 6ms 18 Apr 2025 656th CaedenHarper 🇨🇦 0 58 4ms 18 Apr 2025 656th dokutan 0 58 3ms 28 Apr 2025 656th 2bular 0 58 3ms 8 Jul 2025 656th h3ra993huskp 🇯🇵 0 58 4,348ms 11 Aug 2025 656th frankgraziano 0 58 6ms 13 Aug 2025 656th snoozingnewt 🇨🇦 0 58 6ms 15 Sep 2025 656th snoozingnewt 🇨🇦 0 58 4ms 15 Sep 2025 656th snoozingnewt 🇨🇦 0 58 3ms 15 Sep 2025 656th kg583 🇺🇸 0 58 4ms 27 Sep 2025 656th plcc0 0 58 6ms 7 Oct 2025 656th TheZwierzLF 🇵🇱 0 58 535ms 21 Nov 2025 656th JOrE20 0 58 6ms 25 Nov 2025 701st MeWhenI 🇻🇦 0 59 6ms 11 Dec 2024 701st emgordon154 0 59 4ms 8 Jan 2025 701st duckyluuk 🇳🇱 0 59 6ms 12 Jan 2025 701st Natanaelel 🇸🇪 0 59 4ms 2 Feb 2025 701st ovs-code 🇩🇪 0 59 14ms 4 Feb 2025 701st Shanethegamer 🇺🇸 0 59 3ms 7 Feb 2025 701st voytxt 🇨🇿 0 59 6ms 8 Feb 2025 701st GolfingSuccess 🇬🇷 0 59 14ms 15 Feb 2025 701st 2bular 0 59 14ms 5 Mar 2025 701st DialFrost 🇸🇬 0 59 15ms 17 Apr 2025 701st zacjl 0 59 15ms 17 Apr 2025 701st Shanethegamer 🇺🇸 0 59 15ms 17 Apr 2025 701st HumanoidCPU 0 59 15ms 18 Apr 2025 701st dokutan 0 59 15ms 28 Apr 2025 701st edsrzf 🇳🇿 0 59 14ms 13 Jun 2025 701st LostSyntax21 🇬🇧 0 59 4ms 19 Jul 2025 701st snoozingnewt 🇨🇦 0 59 14ms 15 Sep 2025 701st gaving-quadprep 0 59 60ms 26 Oct 2025 701st FlyingPenguin223 0 59 2ms 14 Nov 2025 701st MeWhenI 🇻🇦 0 59 3ms 14 Nov 2025 First Prev 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