The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 2 days. Why not try and solve them ahead of time?
Kolakoski Sequence 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 878th hiichbindermax 675 73 11ms 26 Feb 2022 878th Omega65536 🇩🇪 675 73 11ms 24 Nov 2022 878th sandorstormen 675 73 11ms 18 Feb 2023 878th Mr-McChicken 675 73 10ms 15 Oct 2023 878th Masttest 675 73 10ms 21 Feb 2024 886th dokutan 675 99 372ms 24 Sep 2025 887th janbehrens 🇩🇪 673 68 1,239ms 9 Apr 2021 888th madex 🇩🇪 673 79 2ms 11 Jul 2024 889th msbranicky 672 80 4ms 11 Oct 2023 890th I-Love-47 🇺🇦 671 106 62ms 10 Feb 2022 891st 5quiwyrm 670 54 293ms 5 Dec 2024 892nd DialFrost 🇸🇬 666 56 83ms 22 Jul 2024 893rd CaedenHarper 🇨🇦 666 70 11ms 31 Jan 2025 894th jameslindesay 666 74 11ms 24 Feb 2021 894th PkmnQ 666 74 37ms 5 May 2024 894th RedzGoose 🇦🇺 666 74 11ms 14 Oct 2024 894th yokasuretsu 666 74 11ms 13 Jan 2025 898th Natanaelel 🇸🇪 663 56 4ms 20 Jan 2024 899th MeWhenI 🇻🇦 663 69 312ms 15 Feb 2023 899th MarcMush 🇫🇷 663 69 304ms 12 Feb 2024 899th Yewzir 🇧🇪 663 69 398ms 5 Apr 2024 902nd DialFrost 🇸🇬 663 75 163ms 3 Jun 2025 903rd dokutan 662 69 1,041ms 30 Aug 2025 904th 77Tigers 662 114 149ms 9 Apr 2024 905th SirBogman 🇺🇸 659 108 61ms 3 Jan 2022 906th CaedenHarper 🇨🇦 658 36 51ms 17 days ago 907th uttumuttu 🇫🇮 657 71 9ms 8 Jan 2022 907th olleicua 🇺🇸 657 71 9ms 20 Feb 2024 909th Trunksistor 🇫🇷 657 75 11ms 25 May 2022 909th celiendonze 🇨🇭 657 75 12ms 16 Jun 2023 909th qwjhvbxi 657 75 11ms 9 Feb 2024 909th wenbang24 657 75 14ms 6 Apr 2024 913th annaproxy 656 91 96ms 13 Jan 2023 914th AdrienHache 🇫🇷 655 91 406ms 31 Dec 2023 915th emgordon154 653 65 146ms 6 Sep 2024 916th albanian-laundromat 653 98 39ms 28 Nov 2025 917th olivermrose 🇺🇸 652 57 3ms 24 Aug 2021 918th boxjelly 649 65 41ms 11 Feb 2021 918th msbranicky 649 65 38ms 12 Sep 2023 920th jwhear 🇺🇸 649 171 1,847ms 1 Oct 2024 921st Waffle3z 648 76 14ms 20 Jan 2021 921st hellwue 648 76 11ms 16 Nov 2023 921st yuchuehw 648 76 17ms 18 Jan 2024 924th johnnythedoggie 644 106 121ms 3 Mar 2021 924th snoozingnewt 🇨🇦 644 106 99ms 21 Nov 2025 926th rboath 643 58 83ms 8 Jan 2025 927th NickTheEASDude 🇺🇸 642 95 1ms 1 Jul 2024 928th Shanethegamer 🇺🇸 641 97 9ms 22 Dec 2023 929th msbranicky 641 134 294ms 3 Oct 2023 930th nephila-nacrea 🇬🇧 640 58 3ms 3 Feb 2021 931st f-tucker 640 77 11ms 2 Feb 2024 931st undefinedRyan 640 77 14ms 19 Apr 2025 931st Emutis 🇱🇹 640 77 12ms 12 Sep 2025 934th alomiF 640 102 124ms 4 Nov 2024 935th Maznek 639 73 10ms 30 Jun 2023 936th Bubbler-4 639 97 72ms 13 Sep 2023 937th MeWhenI 🇻🇦 637 82 10ms 21 Jul 2023 938th janbehrens 🇩🇪 636 135 282ms 13 Jun 2021 939th Shanethegamer 🇺🇸 635 57 258ms 27 Jul 2023 940th MateuszPietrzak 🇵🇱 635 112 55ms 16 Jan 2024 941st sreyfe 635 119 156ms 9 Jun 2024 942nd dokutan 634 94 392ms 18 Jul 2025 943rd emgordon154 634 98 10ms 10 Dec 2024 944th DialFrost 🇸🇬 633 67 154ms 3 Aug 2024 945th SirBogman 🇺🇸 633 84 2ms 14 Dec 2021 946th MeWhenI 🇻🇦 633 90 2,844ms 24 Oct 2024 947th AkashTandon167 632 78 11ms 25 May 2021 947th jhpaques 🇫🇷 632 78 20ms 30 Nov 2022 949th emgordon154 632 186 1,426ms 30 May 2025 950th janbehrens 🇩🇪 631 136 25ms 9 Jul 2021 951st NewDefectus 🇮🇱 630 59 6ms 25 Oct 2021 952nd Protothor 630 74 10ms 9 days ago 953rd Shanethegamer 🇺🇸 625 64 2ms 26 Jul 2023 954th twocatsinatrenchcoat 624 79 9ms 29 Mar 2022 954th SniperSmiley 🇺🇸 624 79 41ms 23 Jun 2022 954th Glinte 624 79 17ms 14 Dec 2023 954th Bmrl7 624 79 13ms 19 Mar 2024 954th acotis 624 79 12ms 21 days ago 959th CaedenHarper 🇨🇦 624 107 492ms 6 Oct 2025 960th edsrzf 🇳🇿 622 138 294ms 21 Dec 2024 First Prev 881–960 of 1,923 Next Last