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?
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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 561st hellwue 775 89 10ms 8 Feb 2023 561st elgan65536 🇺🇸 775 89 16ms 29 Mar 2024 561st AdamMorris377 775 89 10ms 29 Jul 2024 561st RaBa21 🇭🇺 775 89 17ms 19 Jul 2025 565th DialFrost 🇸🇬 774 91 2,754ms 25 Oct 2024 566th xsot 🇸🇬 773 58 39ms 6 Jul 2025 566th sean-niemann 🇺🇸 773 58 35ms 3 Aug 2025 568th LHLaurini 🇧🇷 773 119 1ms 17 Jul 2024 568th solisolu 773 119 1ms 25 Nov 2025 570th andersk 🇺🇸 773 156 235ms 30 Oct 2022 570th emgordon154 773 156 249ms 14 Mar 2025 572nd primo-ppcg 🇹🇭 772 131 6ms 20 Jan 2023 573rd kmathis22 772 138 486ms 30 Oct 2025 574th nwellnhof 🇩🇪 771 54 4ms 22 May 2022 575th clockworknazo 771 85 4ms 25 Mar 2023 576th call23re 771 112 2ms 12 Jan 2022 577th primo-ppcg 🇹🇭 771 118 373ms 9 Apr 2022 578th strout 771 145 148ms 15 Aug 2022 579th scpchicken 🇵🇼 769 55 135ms 13 Mar 2022 580th MeWhenI 🇻🇦 769 130 41ms 30 Dec 2025 581st Shanethegamer 🇺🇸 769 157 151ms 8 Oct 2022 582nd maxpelic 🇺🇸 768 92 10ms 5 Jul 2022 582nd astdefu 768 92 10ms 10 Dec 2022 582nd two-bad 🇬🇧 768 92 12ms 25 Feb 2024 582nd dokutan 768 92 11ms 15 Jun 2025 586th Steffan153 🇫🇮 768 132 14ms 5 Jul 2024 587th Shanethegamer 🇺🇸 766 76 402ms 12 Oct 2022 588th sjrct 766 90 10ms 5 Aug 2024 588th webmiche 766 90 10ms 3 Nov 2025 590th frankgraziano 766 130 7ms 22 Feb 2026 591st ovs-code 🇩🇪 765 34 41ms 14 May 2024 592nd juliansiebert 🇩🇪 765 72 350ms 24 Jul 2022 593rd stefangimmillaro 765 76 1,333ms 8 Jan 2023 593rd MeWhenI 🇻🇦 765 76 1,213ms 10 May 2023 593rd error256 765 76 1,384ms 14 Feb 2025 596th albanian-laundromat 763 76 963ms 7 Nov 2025 597th Yewzir 🇧🇪 763 115 195ms 26 Dec 2023 598th jerrandolph 762 174 294ms 20 Oct 2023 599th rak1507 🇬🇧 761 40 2ms 10 Jan 2022 599th Frowny 761 40 2ms 13 Jan 2022 599th razetime 761 40 2ms 22 Aug 2022 602nd MeWhenI 🇻🇦 761 43 4ms 1 Mar 2025 603rd DialFrost 🇸🇬 761 133 6ms 11 Dec 2024 604th MeWhenI 🇻🇦 760 59 35ms 24 Aug 2022 604th janlelis 760 59 36ms 21 Sep 2024 606th emgordon154 760 81 403ms 1 Aug 2024 607th Andrey-Plotnikov 760 93 11ms 21 Jun 2025 607th Protothor 760 93 10ms 9 Jul 2025 609th retrohun 760 121 1ms 30 Dec 2022 609th abc7-12 760 121 1ms 26 Jun 2024 611th kejcao 🇨🇦 760 147 152ms 3 Aug 2024 612th primo-ppcg 🇹🇭 758 67 15ms 24 Jan 2022 613th P-Quentin 🇫🇷 758 91 11ms 5 Aug 2022 613th Rubiksmath 758 91 16ms 28 Jun 2024 613th wh3n3v3r 🇨🇿 758 91 10ms 11 Nov 2024 616th GrayJoKing 🇦🇺 758 126 458ms 1 Mar 2022 617th xsot 🇸🇬 757 55 3ms 6 Jul 2025 618th dokutan 757 81 130ms 15 Jun 2025 619th edsrzf 🇳🇿 757 93 2,784ms 1 Sep 2025 620th DialFrost 🇸🇬 757 114 2ms 1 Nov 2024 621st edsrzf 🇳🇿 757 132 43ms 31 Dec 2025 622nd annaproxy 757 134 15ms 24 Dec 2022 623rd MeWhenI 🇻🇦 757 146 57ms 13 Nov 2022 623rd janbehrens 🇩🇪 757 146 57ms 23 Jun 2023 625th MeWhenI 🇻🇦 757 194 1,694ms 7 Nov 2025 626th Shanethegamer 🇺🇸 754 73 263ms 14 Jun 2024 627th c0d3-4-F00d 🇩🇪 754 122 2ms 21 Feb 2022 628th ovs-code 🇩🇪 753 87 4ms 8 Mar 2023 629th MeWhenI 🇻🇦 753 128 8ms 21 Jul 2023 630th tomh1012 752 94 10ms 13 days ago 631st Ripick 752 121 360ms 11 Jul 2024 632nd DialFrost 🇸🇬 752 142 2ms 14 Sep 2024 633rd albanian-laundromat 751 133 42ms 7 Sep 2025 634th edsrzf 🇳🇿 751 173 41ms 28 Jun 2025 635th Starwort 🇬🇧 750 92 10ms 17 Mar 2023 635th cingulataluke 750 92 10ms 29 Aug 2023 637th JOrE20 750 179 26ms 18 Feb 2026 638th edsrzf 🇳🇿 749 97 62ms 7 Oct 2025 639th Steffan153 🇫🇮 749 135 6ms 12 Mar 2023 640th elgan65536 🇺🇸 749 161 150ms 9 Nov 2023 First Prev 561–640 of 1,610 Next Last