The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 17 hours. Why not try and solve them ahead of time?
Set 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 241st nwellnhof 🇩🇪 681 73 79ms 6 Apr 2025 242nd error256 681 118 33ms 27 Apr 2025 242nd orthoplex 🇨🇽 681 118 28ms 3 Jun 2025 242nd ovs-code 🇩🇪 681 118 30ms 17 Nov 2025 245th BlankSpruce 679 206 72ms 14 Apr 2025 246th Kacarott 🇦🇺 675 126 627ms 6 Apr 2025 247th Shanethegamer 🇺🇸 675 210 1,430ms 27 Mar 2025 248th emgordon154 673 49 18ms 22 days ago 249th GrayJoKing 🇦🇺 671 74 68ms 1 Apr 2025 249th error256 671 74 43ms 8 May 2025 251st snoozingnewt 🇨🇦 671 187 183ms 30 Oct 2025 252nd error256 667 303 70ms 25 Apr 2025 253rd jerrandolph 665 270 364ms 24 Sep 2025 254th DanielVenable 664 189 202ms 26 Mar 2025 255th Yax42 🇫🇷 661 136 14ms 20 Jan 2026 256th stefangimmillaro 661 174 420ms 4 Jun 2025 257th zacjl 659 122 126ms 29 Mar 2025 258th MeWhenI 🇻🇦 659 244 551ms 7 Nov 2025 259th janAkali 🇷🇺 655 195 441ms 21 days ago 260th anter69 🇭🇺 654 76 426ms 24 Mar 2025 260th stefangimmillaro 654 76 67ms 8 Apr 2025 262nd AlephSquirrel 654 123 85ms 16 Jan 2025 262nd Natanaelel 🇸🇪 654 123 27ms 31 Mar 2025 262nd lynn 654 123 27ms 7 Apr 2025 262nd BlankSpruce 654 123 28ms 13 Apr 2025 262nd m-tkach 🇺🇦 654 123 29ms 14 Apr 2025 262nd Bulmenisaurus 654 123 28ms 30 Jun 2025 262nd SirBogman 🇺🇸 654 123 28ms 1 Jul 2025 262nd edsrzf 🇳🇿 654 123 27ms 27 Sep 2025 262nd bzijlema 🇳🇱 654 123 27ms 28 Nov 2025 262nd ryyyn 🇺🇸 654 123 27ms 7 Feb 2026 272nd ovs-code 🇩🇪 654 130 666ms 6 Apr 2025 273rd Shanethegamer 🇺🇸 654 192 183ms 27 Mar 2025 274th emgordon154 653 177 153ms 27 Mar 2025 275th Shanethegamer 🇺🇸 652 114 559ms 8 Mar 2025 276th edsrzf 🇳🇿 652 202 170ms 27 Apr 2025 277th btnlq 648 124 26ms 6 Jan 2025 277th inventshah 648 124 32ms 31 Mar 2025 277th Lv0Sys 🇵🇱 648 124 26ms 10 Dec 2025 277th blaztoma 🇱🇹 648 124 27ms 17 Jan 2026 281st Lv0Sys 🇵🇱 647 139 16ms 22 Feb 2026 282nd SirBogman 🇺🇸 643 73 342ms 10 Jul 2025 283rd davecame 643 125 23ms 12 Apr 2025 284th DialFrost 🇸🇬 640 114 323ms 24 Jun 2025 285th CLOStrophobic 🇮🇹 639 212 3,887ms 22 Apr 2025 286th Shanethegamer 🇺🇸 638 126 26ms 13 Feb 2025 286th annaproxy 638 126 27ms 7 Apr 2025 286th 5cw 🇺🇸 638 126 27ms 30 May 2025 286th 051 🇸🇬 638 126 27ms 16 Feb 2026 290th KatieLG 🇬🇧 637 78 64ms 2 Oct 2025 291st sean-niemann 🇺🇸 635 253 541ms 18 Dec 2025 292nd anter69 🇭🇺 634 120 1,555ms 1 Apr 2025 293rd DialFrost 🇸🇬 633 127 31ms 18 Feb 2025 293rd bizy-coder 633 127 33ms 18 Feb 2025 293rd bricknellj 633 127 27ms 28 Mar 2025 293rd cros107 🇦🇺 633 127 27ms 30 Mar 2025 293rd souta-1326 633 127 29ms 1 Apr 2025 293rd bknower 633 127 28ms 29 Jun 2025 299th HumanoidCPU 628 128 38ms 29 Mar 2025 299th scpchicken 🇵🇼 628 128 27ms 13 Apr 2025 299th stefangimmillaro 628 128 99ms 28 Apr 2025 299th MeWhenI 🇻🇦 628 128 28ms 13 Jul 2025 299th solisolu 628 128 27ms 4 Dec 2025 299th StefanHabel 🇨🇦 628 128 31ms 5 days ago 305th duckyluuk 🇳🇱 625 119 569ms 6 Jul 2025 306th CaedenHarper 🇨🇦 625 257 526ms 6 Oct 2025 307th neihousaigaai 623 129 19ms 5 Apr 2025 307th ahmetdemirag 🇨🇾 623 129 27ms 5 Apr 2025 307th snoozingnewt 🇨🇦 623 129 1,054ms 6 Dec 2025 310th commandz0 🇺🇸 619 120 509ms 1 Sep 2025 310th KatieLG 🇬🇧 619 120 545ms 22 Sep 2025 312th GrayJoKing 🇦🇺 618 130 41ms 1 Apr 2025 312th rollershutter 618 130 27ms 8 Apr 2025 312th InigoK 🇺🇸 618 130 27ms 19 Sep 2025 315th Natanaelel 🇸🇪 617 108 1,130ms 26 Mar 2025 316th AlephSquirrel 614 121 567ms 31 Mar 2025 316th SirBogman 🇺🇸 614 121 497ms 1 Jul 2025 318th commandz0 🇺🇸 614 131 30ms 28 Mar 2025 319th elgan65536 🇺🇸 612 254 262ms 7 Feb 2026 320th m-tkach 🇺🇦 609 122 527ms 21 Apr 2025 First Prev 241–320 of 492 Next Last