The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 8 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 881st Yewzir 🇧🇪 763 102 217ms 7 May 2024 882nd primo-ppcg 🇹🇭 763 132 3ms 14 Nov 2022 883rd LeeCamp 762 27 33ms 10 Feb 2022 884th snoozingnewt 🇨🇦 762 154 306ms 29 Oct 2025 885th dokutan 761 67 3ms 24 days ago 886th pardouin 🇫🇷 760 51 62ms 13 Sep 2024 887th DialFrost 🇸🇬 757 164 121ms 15 Dec 2025 888th SirFireball3521 755 52 9ms 3 Nov 2022 888th albanian-laundromat 755 52 10ms 24 Nov 2025 890th namelessiw 752 49 449ms 19 Aug 2024 891st PrathamMehta08 752 57 12ms 6 Dec 2023 891st Terobero 752 57 11ms 21 Aug 2024 891st AtengChen 752 57 11ms 7 Sep 2024 891st Mick-Travis 752 57 12ms 8 Dec 2024 895th pardouin 🇫🇷 752 84 129ms 8 Mar 2025 896th MeWhenI 🇻🇦 752 156 307ms 10 Feb 2023 897th Jeremy-Stafford 751 61 124ms 28 Feb 2023 897th inverseLorentz 🇦🇺 751 61 124ms 23 Apr 2024 899th dokutan 751 66 1,236ms 24 days ago 900th pardouin 🇫🇷 750 68 6ms 26 Apr 2025 901st MeWhenI 🇻🇦 749 219 110ms 16 Aug 2024 902nd snoozingnewt 🇨🇦 747 47 946ms 21 Nov 2025 903rd Alex-x90 🇺🇸 747 147 560ms 6 May 2024 904th ovs-code 🇩🇪 747 161 137ms 21 Apr 2025 905th MeWhenI 🇻🇦 746 60 9ms 29 Jan 2022 906th Shanethegamer 🇺🇸 744 85 112ms 14 Oct 2022 906th edsrzf 🇳🇿 744 85 113ms 30 Apr 2025 908th nipzu 742 162 128ms 2 Apr 2024 909th snoozingnewt 🇨🇦 741 48 31ms 3 Dec 2025 910th jbjd 739 58 9ms 25 Feb 2024 911th Steffan153 🇫🇮 738 29 116ms 14 Nov 2022 911th ovs-code 🇩🇪 738 29 145ms 29 Dec 2023 913th CheeseCake628 🇳🇴 737 50 498ms 18 Oct 2025 914th dpinchbe 735 28 33ms 6 Sep 2024 915th edsrzf 🇳🇿 734 289 42ms 11 Feb 2026 916th madex 🇩🇪 731 42 34ms 8 days ago 917th MeWhenI 🇻🇦 731 53 65ms 5 Apr 2025 918th ovs-code 🇩🇪 729 70 8ms 11 Dec 2023 918th DialFrost 🇸🇬 729 70 6ms 1 Jan 2026 920th CaedenHarper 🇨🇦 729 161 306ms 20 Nov 2025 921st madex 🇩🇪 728 68 1,303ms 8 days ago 922nd dvargas46 🇺🇸 728 158 829ms 5 Feb 2023 923rd iczelia 🇩🇪 727 54 9ms 14 Oct 2025 924th Shanethegamer 🇺🇸 725 73 5ms 4 Oct 2024 925th snoozingnewt 🇨🇦 725 164 95ms 8 Feb 2026 926th Stockoh 🇫🇷 723 51 404ms 23 Jun 2024 927th h3ra993huskp 🇯🇵 723 150 429ms 30 Nov 2025 928th davbass 🇮🇹 721 51 248ms 22 Aug 2023 929th emgordon154 720 163 291ms 18 Jan 2025 930th primo-ppcg 🇹🇭 719 160 73ms 4 Feb 2023 931st SniperSmiley 🇺🇸 716 25 39ms 4 Sep 2022 932nd Irratix 🇳🇱 716 64 125ms 29 Jan 2022 933rd msbranicky 715 164 296ms 31 Aug 2023 934th snoozingnewt 🇨🇦 714 43 38ms 26 Sep 2025 935th LeeCamp 714 60 10ms 9 Feb 2022 935th guilhem-roy 🇫🇷 714 60 10ms 22 Feb 2022 935th Eilonlif 🇮🇱 714 60 10ms 27 Aug 2022 935th LogicalJoe 714 60 10ms 18 Sep 2022 935th 5quiwyrm 714 60 10ms 22 Oct 2022 935th TaserTheFox 🇺🇸 714 60 9ms 9 Jan 2023 935th ljweel 714 60 10ms 13 Feb 2023 935th shellbertt 🇨🇦 714 60 10ms 27 Apr 2023 935th ssbhatt4321 714 60 10ms 11 Jun 2023 935th PeterTillema 🇳🇱 714 60 10ms 10 Oct 2023 935th kurkale6ka 714 60 9ms 21 Dec 2023 935th sultan 714 60 9ms 3 Mar 2024 935th alemelis 714 60 10ms 13 Oct 2024 935th csharpython 714 60 10ms 5 Aug 2025 935th BREMAUCY 🇫🇷 714 60 10ms 11 Aug 2025 935th denkyuu1 714 60 11ms 16 Feb 2026 951st dokutan 714 109 232ms 18 Mar 2025 952nd Steffan153 🇫🇮 714 297 193ms 30 Jun 2024 953rd MeWhenI 🇻🇦 713 57 77ms 1 Jun 2022 954th qwertyuiop3 🇷🇺 713 154 102ms 26 May 2025 955th kevinnaviapaiva 708 24 2ms 20 days ago 956th typeswitch-dev 🇵🇹 708 217 4ms 24 Jul 2023 957th rokasveitas 🇱🇹 707 52 246ms 16 May 2022 957th shellbertt 🇨🇦 707 52 216ms 19 Mar 2023 959th MeWhenI 🇻🇦 706 75 5ms 14 Feb 2025 960th aDwarfNamedUrist 705 65 124ms 9 Oct 2023 First Prev 881–960 of 2,048 Next Last