The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 6 days. Why not try and solve them ahead of time?
Catalan Numbers in all languages in chars. 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 Chars Time Submitted 801st tatzyr 🇯🇵 808 38 36ms 14 Nov 2024 802nd dokutan 806 90 442ms 26 days ago 803rd blaztoma 🇱🇹 804 57 120ms 22 Aug 2025 804th kmathis22 804 135 477ms 23 Oct 2025 805th jerrandolph 804 146 277ms 23 Sep 2025 806th MeWhenI 🇻🇦 803 97 212ms 2 Jul 2023 807th albanian-laundromat 803 117 1,416ms 5 Oct 2025 808th MeWhenI 🇻🇦 802 227 309ms 29 Dec 2024 809th JOrE20 801 46 360ms 23 Feb 2026 810th Feniske 🇫🇷 800 38 294ms 6 Nov 2023 810th Yewzir 🇧🇪 800 38 264ms 7 May 2024 812th emplv 🇱🇻 800 79 115ms 20 Dec 2022 812th DialFrost 🇸🇬 800 79 114ms 23 Mar 2025 814th j-Ewan 799 46 481ms 11 Feb 2022 814th czylabsonasa 🇭🇺 799 46 266ms 14 Jun 2022 816th albanian-laundromat 798 44 1,034ms 25 Sep 2025 816th Yewzir 🇧🇪 798 44 998ms 15 Nov 2025 818th dokutan 798 136 469ms 7 Nov 2025 819th Betuaredead 798 147 289ms 21 Jan 2023 820th error256 797 51 77ms 15 Jan 2025 821st MeWhenI 🇻🇦 797 85 2,654ms 27 Oct 2024 822nd Matgc04 797 91 386ms 17 Nov 2023 823rd msbranicky 794 54 10ms 23 Aug 2023 823rd Code-Coder-coder 794 54 10ms 12 Oct 2025 825th Ripick 793 148 286ms 16 Feb 2023 826th MeWhenI 🇻🇦 790 45 29ms 16 Apr 2023 827th Shanethegamer 🇺🇸 789 92 368ms 29 Jan 2022 828th dokutan 788 79 478ms 26 days ago 829th Yewzir 🇧🇪 787 39 35ms 7 May 2024 829th codereport 🇨🇦 787 39 32ms 21 Apr 2025 829th Chara-0x 787 39 35ms 18 Sep 2025 829th dokutan 787 39 36ms 26 days ago 833rd stefangimmillaro 787 86 2,662ms 4 Nov 2024 834th xsot 🇸🇬 787 128 70ms 13 Jun 2025 835th didion0 🇺🇸 785 50 10ms 16 Feb 2022 835th Natanaelel 🇸🇪 785 50 9ms 3 Jan 2024 835th weliveinhell 🇭🇹 785 50 9ms 11 Jan 2024 835th inverseLorentz 🇦🇺 785 50 12ms 1 Apr 2024 839th annaproxy 785 65 3ms 3 Oct 2022 839th Shanethegamer 🇺🇸 785 65 7ms 19 Dec 2023 841st KatieLG 🇬🇧 784 47 437ms 15 Jan 2024 841st Yewzir 🇧🇪 784 47 347ms 7 May 2024 843rd stellartux 782 47 289ms 1 Jan 2024 844th albanian-laundromat 781 52 72ms 24 Dec 2025 845th jared-hughes 781 139 501ms 24 Sep 2025 846th stefangimmillaro 781 159 29ms 4 May 2023 847th blaztoma 🇱🇹 780 39 269ms 25 Nov 2025 848th hamhub7 780 93 377ms 3 Aug 2022 848th MeWhenI 🇻🇦 780 93 383ms 15 Oct 2022 850th 2011-Chan-Ethan 779 55 10ms 14 Jul 2023 850th cuboids 779 55 10ms 10 Jul 2024 850th jatloe 779 55 11ms 27 Sep 2024 850th Emutis 🇱🇹 779 55 11ms 27 Oct 2024 854th KasperKivimaeki 🇫🇮 779 147 5ms 4 Jun 2025 855th MeWhenI 🇻🇦 778 23 40ms 25 Jul 2022 855th AlephSquirrel 778 23 42ms 31 Dec 2022 857th DialFrost 🇸🇬 778 68 5ms 7 Dec 2024 857th pardouin 🇫🇷 778 68 5ms 20 Mar 2025 859th Shanethegamer 🇺🇸 777 59 122ms 29 Jan 2022 859th Z-snails 777 59 129ms 28 Feb 2023 861st kimbo 🇺🇸 777 151 276ms 25 Dec 2022 862nd rak1507 🇬🇧 776 52 31ms 29 Jan 2022 863rd KatieLG 🇬🇧 774 64 1,294ms 16 Oct 2022 864th jared-hughes 774 307 21ms 8 Jul 2024 865th inventshah 773 22 2ms 8 May 2022 866th Natanaelel 🇸🇪 773 46 30ms 3 Jan 2024 867th Shanethegamer 🇺🇸 772 58 14ms 29 Jan 2022 868th primo-ppcg 🇹🇭 772 332 66ms 25 Jun 2022 869th ovs-code 🇩🇪 771 82 117ms 14 Oct 2022 870th codingisgreatbutiamnot 770 51 10ms 25 Jul 2024 871st Yax42 🇫🇷 769 141 504ms 4 Oct 2025 872nd albanian-laundromat 768 48 442ms 7 Oct 2025 873rd dokutan 767 153 301ms 24 Mar 2025 874th MeWhenI 🇻🇦 766 48 339ms 15 Feb 2023 875th petroselo 765 56 9ms 12 Apr 2022 875th SB-945 765 56 10ms 10 Jul 2023 875th JunkIce 765 56 10ms 24 Nov 2024 875th kevinnaviapaiva 765 56 10ms 19 Dec 2024 875th wobblybits 765 56 10ms 19 Aug 2025 880th brimstonetrader 764 60 125ms 10 Jan 2024 First Prev 801–880 of 2,051 Next Last