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 801st MeWhenI 🇻🇦 717 75 8ms 9 Oct 2023 802nd prplz 🇦🇺 717 91 118ms 25 Jan 2021 803rd marshallward 🇺🇸 716 100 41ms 7 May 2025 804th tatzyr 🇯🇵 715 59 37ms 29 Dec 2024 805th NewDefectus 🇮🇱 714 21 2ms 14 Jan 2022 806th prplz 🇦🇺 714 52 3ms 5 Feb 2021 807th abailey2020 🇺🇸 714 69 10ms 19 Feb 2021 807th Anonymousellama21 714 69 12ms 15 May 2022 807th TaserTheFox 🇺🇸 714 69 38ms 16 Feb 2023 807th Jacob385 714 69 43ms 22 Apr 2024 811th emgordon154 712 80 2,629ms 9 Aug 2025 812th MeWhenI 🇻🇦 711 90 1,365ms 14 Jun 2023 813th chordowl 710 92 116ms 17 Mar 2021 814th marcin7Cd 710 103 21ms 12 Feb 2021 815th Feniske 🇫🇷 709 51 272ms 21 Nov 2023 816th CaedenHarper 🇨🇦 709 84 392ms 17 Oct 2025 817th aadenboy 🇺🇸 709 86 2ms 16 Dec 2025 818th rucin93 🇵🇱 707 60 136ms 9 Aug 2024 819th omurakazuaki 🇯🇵 706 66 10ms 18 Feb 2021 819th BambooleanLogic 🇸🇪 706 66 12ms 22 Aug 2022 819th coreynash 706 66 9ms 21 Oct 2023 819th two-bad 🇬🇧 706 66 12ms 24 Nov 2023 819th dylanarmstrong 706 66 10ms 15 Jan 2024 819th madeforlosers 706 66 10ms 5 Nov 2025 825th Stockoh 🇫🇷 706 68 427ms 24 Jun 2024 825th JunkIce 706 68 442ms 3 Dec 2024 827th typeswitch-dev 🇵🇹 705 74 8ms 7 Aug 2023 828th antimon2 🇯🇵 704 65 495ms 19 Jan 2021 828th msbranicky 704 65 1,289ms 12 Sep 2023 830th osmith93 704 70 25ms 14 Jun 2021 830th ridingqwerty 🇺🇸 704 70 12ms 23 Feb 2024 830th mbittner20 704 70 11ms 15 Jul 2024 830th RaBa21 🇭🇺 704 70 12ms 18 Jul 2025 834th Shanethegamer 🇺🇸 704 91 39ms 16 Jun 2022 835th Herbert00709 🇵🇱 704 101 60ms 19 Nov 2024 836th SnowballSH 703 60 36ms 12 Feb 2021 836th aksyristos 703 60 37ms 28 Feb 2023 836th Lv0Sys 🇵🇱 703 60 40ms 4 Dec 2025 839th primo-ppcg 🇹🇭 702 47 1,032ms 5 Feb 2022 840th MeWhenI 🇻🇦 702 238 12ms 29 Aug 2023 841st UnderKoen 🇳🇱 700 134 13ms 20 Jan 2025 842nd jared-hughes 699 44 6ms 31 Jul 2022 843rd NewDefectus 🇮🇱 699 76 2ms 25 Oct 2021 843rd JohandeRuiter 🇳🇱 699 76 2ms 3 Dec 2023 845th Shanethegamer 🇺🇸 699 77 13ms 9 Oct 2023 846th targrik 698 123 305ms 10 Jul 2025 847th jared-hughes 698 159 1,670ms 16 Sep 2025 848th AlephSquirrel 697 34 51ms 30 Dec 2022 849th targrik 696 57 5ms 26 Aug 2025 850th neihousaigaai 696 67 9ms 10 Apr 2021 851st Jacob385 696 69 436ms 22 Apr 2024 852nd SnowballSH 694 71 11ms 12 Feb 2021 852nd Andre3582 694 71 11ms 18 Mar 2021 852nd PhysicDev 🇫🇷 694 71 10ms 20 May 2021 852nd Alban-Boissard 694 71 12ms 10 Jun 2025 856th boxjelly 694 94 114ms 21 Jan 2021 856th YAJUE114514 694 94 133ms 24 Jul 2025 858th Espiobest 692 61 34ms 13 Feb 2021 858th DaCuteRaccoon 692 61 42ms 9 Dec 2022 860th JGDoerrer 691 103 445ms 5 Jan 2022 860th tailorspy 691 103 59ms 29 Oct 2023 862nd Shanethegamer 🇺🇸 690 106 17ms 4 Oct 2024 863rd msbranicky 689 95 5ms 11 Aug 2023 864th NewDefectus 🇮🇱 688 32 34ms 20 Dec 2021 865th GolfingSuccess 🇬🇷 688 69 33ms 17 Aug 2024 866th Andriamanitra 🇫🇮 687 95 148ms 20 Jul 2023 867th KasperKivimaeki 🇫🇮 687 125 288ms 3 Oct 2025 868th msbranicky 685 89 2ms 26 Sep 2023 869th LeeCamp 684 72 10ms 16 Feb 2022 869th LukasFolwarczny 🇨🇿 684 72 10ms 16 Sep 2022 869th CutSandstone 684 72 38ms 8 Jul 2024 872nd Shanethegamer 🇺🇸 681 126 24ms 8 Jul 2021 873rd dokutan 678 59 3ms 18 Jul 2025 874th jared-hughes 677 35 48ms 31 Jul 2022 874th Natanaelel 🇸🇪 677 35 50ms 18 Aug 2022 874th CaedenHarper 🇨🇦 677 35 54ms 9 mins ago 877th Yewzir 🇧🇪 677 88 387ms 14 Oct 2023 878th SirBogman 🇺🇸 676 44 214ms 22 Oct 2021 879th richard-oelze 🇩🇪 675 73 30ms 4 Apr 2021 879th mauro-1 🇮🇹 675 73 9ms 18 Aug 2021 First Prev 801–880 of 1,923 Next Last