The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 3 days. Why not try and solve them ahead of time?
Arabic to Roman 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 641st greentruff 672 128 21ms 7 Dec 2025 642nd MeWhenI 🇻🇦 672 141 10ms 1 Feb 2024 643rd Shanethegamer 🇺🇸 671 115 598ms 8 Jan 2022 644th Shanethegamer 🇺🇸 671 185 660ms 28 Jan 2024 644th prestosilver 🇺🇸 671 185 413ms 30 Dec 2025 646th JDiLenarda 🇫🇷 671 205 1,328ms 22 Nov 2023 647th kmathis22 671 216 633ms 19 Dec 2025 648th Shanethegamer 🇺🇸 669 159 175ms 24 May 2025 649th Shanethegamer 🇺🇸 669 214 115ms 28 Jan 2024 650th AlephSquirrel 667 129 20ms 15 Aug 2022 650th 5cw 🇺🇸 667 129 22ms 8 May 2025 652nd DialFrost 🇸🇬 665 112 3,569ms 17 Apr 2025 653rd stackotter 665 227 128ms 29 May 2023 654th Jonatan6 🇩🇰 664 203 89ms 3 Aug 2023 655th Shanethegamer 🇺🇸 664 221 31ms 10 Feb 2026 656th SirBogman 🇺🇸 663 375 614ms 23 Nov 2022 657th primo-ppcg 🇹🇭 662 130 23ms 6 Oct 2021 658th dokutan 661 204 4,456ms 2 Feb 2026 659th Shanethegamer 🇺🇸 661 233 373ms 28 Jan 2024 659th targrik 661 233 332ms 3 Jul 2025 661st MeWhenI 🇻🇦 661 249 170ms 1 Feb 2024 662nd Yewzir 🇧🇪 660 161 225ms 13 Sep 2023 663rd dokutan 659 132 15ms 1 Feb 2026 664th darkoboshkovski 659 155 9ms 12 Jun 2023 665th MeWhenI 🇻🇦 659 176 9ms 16 Jun 2023 666th p-vf 🇨🇭 658 181 406ms 21 Nov 2021 667th scpchicken 🇵🇼 657 70 11ms 6 Jan 2023 668th MichalMarsalek 🇨🇿 657 189 463ms 22 Jan 2023 668th DestyNova 🇮🇪 657 189 456ms 15 Apr 2025 670th annaproxy 656 222 339ms 1 Aug 2022 671st prestosilver 🇺🇸 655 156 11ms 21 Nov 2025 672nd jared-hughes 654 97 40ms 16 Apr 2022 673rd AlephSquirrel 654 133 24ms 15 Feb 2023 673rd jbt 654 133 24ms 25 Dec 2023 675th stefangimmillaro 654 182 452ms 17 Sep 2024 676th clockworknazo 653 140 20ms 27 Feb 2023 677th BlankSpruce 651 207 463ms 26 Aug 2022 678th Jonatan6 🇩🇰 650 157 11ms 4 Aug 2023 679th HumanoidCPU 650 223 664ms 8 Nov 2025 680th janbehrens 🇩🇪 649 134 22ms 12 Nov 2023 681st mokymok 🇺🇸 647 133 22ms 23 Jul 2021 681st evan18c 647 133 24ms 27 Apr 2025 683rd Shanethegamer 🇺🇸 645 147 35ms 28 Jan 2024 684th nsprd 645 209 501ms 19 Jan 2024 685th emgordon154 643 177 3,365ms 9 Aug 2025 686th MeWhenI 🇻🇦 642 116 852ms 1 Feb 2024 687th Fishron 642 134 21ms 21 Oct 2021 688th MeWhenI 🇻🇦 642 159 10ms 25 Aug 2023 689th AlephSquirrel 640 122 509ms 21 Jan 2024 689th JunkIce 640 122 456ms 3 Dec 2024 691st itsh01 640 136 18ms 9 Aug 2021 692nd jared-hughes 640 181 6ms 18 Jul 2022 693rd JGDoerrer 640 257 182ms 15 Feb 2022 694th jared-hughes 639 211 477ms 24 Jun 2022 695th MeWhenI 🇻🇦 636 195 804ms 27 Jul 2024 696th emgordon154 635 123 455ms 1 Aug 2024 697th stefangimmillaro 635 137 17ms 12 Sep 2024 698th xnor-gate 633 136 361ms 4 Dec 2021 698th cingulataluke 633 136 50ms 29 Aug 2023 700th KatieLG 🇬🇧 632 143 1,620ms 17 Nov 2023 701st kkoenig 631 244 320ms 30 Dec 2023 702nd TeodorDyakov 🇧🇬 630 230 554ms 8 Jan 2026 703rd okaponta 630 261 202ms 13 Jan 2024 704th davitf 628 137 19ms 28 Jul 2020 705th emplv 🇱🇻 628 245 353ms 29 Apr 2024 706th tatzyr 🇯🇵 627 97 187ms 18 Dec 2024 707th MeWhenI 🇻🇦 626 151 32ms 16 Aug 2024 708th nwellnhof 🇩🇪 624 138 20ms 28 Jun 2023 708th minhtrancccp 624 138 20ms 26 Nov 2024 710th Lv0Sys 🇵🇱 621 140 14ms 27 Nov 2025 711th Shanethegamer 🇺🇸 621 172 15ms 5 Oct 2024 712th sisyphus-ppcg 🇦🇺 620 98 47ms 25 Sep 2021 713th lifthrasiir 🇰🇷 619 63 8ms 30 Nov 2024 714th leon-w 619 139 31ms 12 Jul 2019 715th chris124567 618 249 384ms 21 Apr 2021 716th jared-hughes 617 141 25ms 10 Sep 2021 716th Andrey-Plotnikov 617 141 13ms 25 Oct 2024 718th MeWhenI 🇻🇦 617 223 1,374ms 16 Jun 2023 719th MeWhenI 🇻🇦 616 66 450ms 28 Jul 2022 720th dokutan 616 122 155ms 1 Feb 2026 First Prev 641–720 of 1,907 Next Last