The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 4 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 399th DialFrost 🇸🇬 828 111 1ms 20 Dec 2024 402nd clockworknazo 828 129 2ms 18 Sep 2022 403rd emplv 🇱🇻 828 160 306ms 6 Jan 2023 403rd KasperKivimaeki 🇫🇮 828 160 293ms 20 Oct 2025 405th Sakisan 🇧🇪 827 64 1,061ms 30 Jun 2022 406th prplz 🇦🇺 827 93 449ms 18 Jan 2022 406th hemphen 827 93 434ms 28 Aug 2022 406th feberhard 827 93 475ms 6 Apr 2023 406th sean-niemann 🇺🇸 827 93 424ms 19 Apr 2025 410th kg583 🇺🇸 827 139 42ms 17 Nov 2025 411th lynn 826 148 30ms 18 Jul 2023 412th jared-hughes 826 200 8ms 18 Dec 2024 413th emplv 🇱🇻 825 101 5ms 3 Jul 2023 413th stefangimmillaro 825 101 4ms 12 Oct 2023 413th edsrzf 🇳🇿 825 101 5ms 7 Oct 2025 416th Mandrzejy 🇵🇱 825 134 79ms 13 Sep 2024 417th MeWhenI 🇻🇦 824 69 5ms 13 Aug 2024 418th SirBogman 🇺🇸 823 37 2ms 27 May 2024 418th Yewzir 🇧🇪 823 37 2ms 19 Dec 2024 420th CLOStrophobic 🇮🇹 823 123 8ms 21 Jan 2025 420th kg583 🇺🇸 823 123 8ms 20 Feb 2026 422nd dcgjb 822 67 292ms 14 Feb 2024 423rd GrayJoKing 🇦🇺 822 130 2ms 12 Sep 2022 424th Bubbler-4 821 48 33ms 15 Nov 2022 424th stackofbears 821 48 32ms 27 Dec 2023 424th 2bular 821 48 33ms 19 days ago 427th duckyluuk 🇳🇱 821 75 416ms 29 Aug 2024 428th jeff-at-tamer-dot-codes 🇺🇸 821 84 10ms 19 May 2023 428th Artemis21 🇬🇧 821 84 11ms 10 Jan 2025 428th Flekay 🇩🇪 821 84 10ms 15 Feb 2026 431st Shanethegamer 🇺🇸 821 112 1ms 20 Apr 2022 432nd Shanethegamer 🇺🇸 820 107 152ms 24 May 2025 433rd m-tkach 🇺🇦 820 130 535ms 25 Sep 2025 434th pardouin 🇫🇷 819 71 1,321ms 2 Sep 2025 435th Irratix 🇳🇱 819 135 452ms 14 May 2022 436th Steffan153 🇫🇮 819 151 33ms 5 days ago 437th DialFrost 🇸🇬 819 286 140ms 22 Apr 2025 437th frankgraziano 819 286 651ms 31 Jan 2026 439th Shanethegamer 🇺🇸 818 63 1ms 13 May 2023 440th annaproxy 818 94 438ms 19 Mar 2022 441st primo-ppcg 🇹🇭 818 164 25ms 25 Jun 2022 442nd o0lit3 🇺🇸 817 51 4ms 11 Jan 2022 443rd MeWhenI 🇻🇦 817 102 5ms 26 Nov 2023 444th JayXon 🇺🇸 816 55 36ms 25 Feb 2022 445th Shanethegamer 🇺🇸 816 124 6ms 27 Aug 2024 446th GrayJoKing 🇦🇺 815 99 4ms 20 Sep 2023 447th Yewzir 🇧🇪 814 113 1ms 29 Nov 2023 447th drabart 🇵🇱 814 113 2ms 18 Dec 2023 449th Shanethegamer 🇺🇸 813 136 56ms 20 Apr 2022 450th sean-niemann 🇺🇸 813 163 298ms 30 Aug 2023 450th Yewzir 🇧🇪 813 163 288ms 7 Feb 2024 450th CaedenHarper 🇨🇦 813 163 288ms 2 Nov 2025 453rd saito-ta 🇯🇵 812 32 42ms 19 Aug 2022 453rd canissimia 🇦🇶 812 32 41ms 19 Aug 2022 455th m42km 812 85 10ms 24 Oct 2023 455th emgordon154 812 85 10ms 1 Aug 2024 455th JunkIce 812 85 10ms 25 Nov 2024 455th robin-scragg 812 85 10ms 25 Jul 2025 459th itsh01 812 87 11ms 13 Mar 2022 459th AlephSquirrel 812 87 11ms 15 Feb 2023 459th danielphilpottwork 812 87 11ms 20 Dec 2023 462nd emgordon154 812 181 1,625ms 22 Dec 2025 463rd btnlq 811 125 15ms 12 Jan 2022 464th Yewzir 🇧🇪 810 76 394ms 22 Jun 2024 464th Shanethegamer 🇺🇸 810 76 406ms 10 Dec 2024 466th stefangimmillaro 810 87 2,700ms 24 Nov 2024 466th emgordon154 810 87 2,768ms 6 Mar 2025 468th DialFrost 🇸🇬 810 118 461ms 27 Nov 2024 469th janbehrens 🇩🇪 809 103 4ms 2 Jul 2023 470th plcc0 809 125 6ms 23 Mar 2025 471st ovs-code 🇩🇪 807 90 65ms 12 Sep 2024 471st primo-ppcg 🇹🇭 807 90 62ms 5 Apr 2025 473rd jotslo 🇬🇧 807 107 2ms 17 Jul 2022 474th Mandrzejy 🇵🇱 807 114 1ms 13 Sep 2024 474th AZTECCO 807 114 1ms 16 Sep 2025 476th error256 807 132 385ms 21 Nov 2025 477th m-tkach 🇺🇦 807 137 56ms 15 Jan 2022 477th sean-niemann 🇺🇸 807 137 58ms 3 Feb 2024 479th DialFrost 🇸🇬 805 72 755ms 4 Sep 2025 480th GrayJoKing 🇦🇺 805 113 401ms 24 Jul 2025 First Prev 401–480 of 1,610 Next Last