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 481st GrayJoKing 🇦🇺 804 152 29ms 18 Jul 2023 481st m-tkach 🇺🇦 804 152 29ms 10 Feb 2026 483rd albanian-laundromat 803 133 3ms 22 Sep 2025 484th emgordon154 802 234 1,451ms 18 Apr 2025 484th error256 802 234 1,485ms 8 Feb 2026 486th 5cw 🇺🇸 801 38 2ms 27 May 2024 486th emgordon154 801 38 3ms 19 days ago 488th ScottHamper 801 96 437ms 26 Feb 2022 488th stefangimmillaro 801 96 419ms 5 Jan 2023 488th bojernico 801 96 449ms 6 Apr 2023 491st h3ra993huskp 🇯🇵 801 133 496ms 30 Nov 2025 492nd KatieLG 🇬🇧 800 77 385ms 28 Oct 2024 493rd madex 🇩🇪 800 115 2ms 10 Apr 2022 493rd FragmentedCurve 800 115 2ms 22 Nov 2023 493rd mathisfun271 800 115 2ms 5 Feb 2024 496th MeWhenI 🇻🇦 799 101 4ms 23 May 2023 497th mtirado1 799 108 2ms 6 May 2023 498th Shanethegamer 🇺🇸 799 168 25ms 28 Apr 2022 499th edsrzf 🇳🇿 798 114 7ms 22 Aug 2025 500th MeWhenI 🇻🇦 797 105 8ms 9 May 2024 501st typeswitch-dev 🇵🇹 797 121 8ms 14 Aug 2023 502nd emgordon154 797 125 6ms 21 days ago 503rd kg583 🇺🇸 797 155 34ms 5 days ago 504th Shanethegamer 🇺🇸 796 84 81ms 9 Jun 2022 505th adyache 🇺🇸 796 91 9ms 2 Aug 2023 506th igmcdowell 794 89 11ms 24 Feb 2022 506th inventshah 794 89 11ms 21 Jun 2022 506th olleicua 🇺🇸 794 89 10ms 3 Feb 2024 506th kpal81xd 794 89 10ms 15 Sep 2024 506th KatieLG 🇬🇧 794 89 10ms 5 Oct 2025 511th stefangimmillaro 794 152 152ms 28 Oct 2023 512th Yewzir 🇧🇪 794 185 1,707ms 21 May 2024 513th gitbedd 🇬🇧 793 87 10ms 10 Jan 2022 513th yzhs 🇩🇪 793 87 10ms 21 Mar 2022 513th CheeseCake628 🇳🇴 793 87 10ms 16 Feb 2023 513th HumanoidCPU 793 87 10ms 2 Mar 2025 517th MeWhenI 🇻🇦 793 116 2ms 5 Jul 2024 518th GolfingSuccess 🇬🇷 792 156 34ms 47 hours ago 519th Shanethegamer 🇺🇸 791 115 374ms 21 Apr 2022 520th ovs-code 🇩🇪 789 153 226ms 21 Jun 2023 521st Steffan153 🇫🇮 787 57 66ms 29 Aug 2024 521st pardouin 🇫🇷 787 57 66ms 2 Sep 2025 523rd prplz 🇦🇺 787 70 305ms 19 Jan 2022 523rd SirBogman 🇺🇸 787 70 295ms 19 May 2022 525th sean-niemann 🇺🇸 787 127 40ms 1 Dec 2023 526th Lydxn 🇨🇦 786 53 4ms 27 Feb 2023 527th ovs-code 🇩🇪 786 85 83ms 27 May 2024 528th KrausRaus 🇺🇸 786 106 4ms 11 Nov 2023 529th m-tkach 🇺🇦 786 117 1ms 11 Jan 2022 529th prestosilver 🇺🇸 786 117 2ms 16 Dec 2025 531st weliveinhell 🇭🇹 785 90 11ms 11 Jan 2024 532nd tomh1012 785 98 437ms 31 Jan 2022 532nd pkim 785 98 450ms 6 Apr 2023 532nd danielxbauer 785 98 459ms 6 Apr 2023 532nd meinsiedler 785 98 412ms 6 Apr 2023 532nd postie77 785 98 461ms 8 May 2023 537th error256 784 74 742ms 13 Feb 2026 538th LHLaurini 🇧🇷 784 141 50ms 17 Jul 2024 539th lynn 784 154 163ms 11 Mar 2022 539th The3gs 784 154 157ms 18 Aug 2023 541st Shanethegamer 🇺🇸 783 90 2,763ms 28 Oct 2024 542nd DialFrost 🇸🇬 783 166 40ms 7 May 2025 543rd Salutations45 781 66 2ms 2 Jan 2025 544th GrayJoKing 🇦🇺 781 93 70ms 9 Dec 2023 545th dokutan 780 79 429ms 15 Aug 2024 545th Babafaba 780 79 387ms 7 Nov 2025 547th MeWhenI 🇻🇦 780 137 2ms 12 Sep 2022 548th imperfect-fourth 780 170 264ms 11 days ago 549th sean-niemann 🇺🇸 779 118 1ms 3 Feb 2024 550th edsrzf 🇳🇿 779 133 1,256ms 26 Apr 2025 551st DialFrost 🇸🇬 779 241 1,422ms 18 Apr 2025 552nd msbranicky 778 112 2ms 10 Oct 2023 553rd AlephSquirrel 778 130 6ms 21 Oct 2024 554th edsrzf 🇳🇿 778 155 294ms 4 days ago 555th albanian-laundromat 778 167 43ms 8 days ago 556th adamnielson42 🇺🇸 777 91 12ms 26 Apr 2023 556th luuumine 🇫🇷 777 91 9ms 12 Nov 2025 558th Skleni 777 99 402ms 6 Apr 2023 559th MichalMarsalek 🇨🇿 777 117 412ms 21 Apr 2022 560th DialFrost 🇸🇬 776 113 151ms 24 May 2025 First Prev 481–560 of 1,610 Next Last