The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 6 days. Why not try and solve them ahead of time?
ln 2 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 639th Cube14yt 640 79 18ms 19 Nov 2025 639th zyc-2024 🇨🇳 640 79 20ms 30 Dec 2025 643rd prestosilver 🇺🇸 639 208 1,053ms 13 days ago 644th msbranicky 636 76 439ms 17 Jan 2024 644th Andrey2001 636 76 420ms 28 Jan 2026 646th prestosilver 🇺🇸 636 154 22ms 2 Dec 2025 647th stefangimmillaro 634 191 302ms 23 Oct 2023 648th h3ra993huskp 🇯🇵 633 180 607ms 30 Nov 2025 649th Natanaelel 🇸🇪 632 38 57ms 3 Aug 2023 650th yuchuehw 632 80 17ms 16 May 2024 650th RaBa21 🇭🇺 632 80 74ms 18 Jul 2025 652nd inventshah 632 155 11ms 1 Aug 2023 653rd dokutan 630 58 57ms 26 Dec 2025 654th primo-ppcg 🇹🇭 629 181 485ms 2 Aug 2023 655th AlephSquirrel 629 202 117ms 3 Aug 2023 656th Alex-x90 🇺🇸 628 156 7ms 24 May 2024 657th jstechman 624 81 69ms 25 Feb 2024 657th robin-scragg 624 81 468ms 28 Sep 2025 659th janbehrens 🇩🇪 623 178 66ms 4 Aug 2023 660th xsot 🇸🇬 620 133 421ms 2 Aug 2023 661st janbehrens 🇩🇪 620 158 7ms 4 Aug 2023 662nd jared-hughes 619 59 46ms 25 Dec 2025 663rd Stockoh 🇫🇷 616 82 19ms 19 Jun 2024 663rd wuzekai518 616 82 2,315ms 21 Jun 2024 665th Alex-x90 🇺🇸 616 180 71ms 1 Aug 2023 666th 2bular 615 46 93ms 4 days ago 667th stefangimmillaro 615 153 51ms 26 Apr 2025 668th NickTheEASDude 🇺🇸 614 63 554ms 8 Aug 2024 669th Mabeloid 🇳🇴 612 79 477ms 17 Sep 2024 670th aksyristos 609 60 47ms 27 Dec 2025 671st roupiq 🇵🇱 609 83 675ms 18 Apr 2024 671st JonahEMorgan 609 83 19ms 10 Nov 2024 673rd MeWhenI 🇻🇦 609 182 70ms 1 Aug 2023 674th SirBogman 🇺🇸 607 385 392ms 1 Aug 2023 675th SirBogman 🇺🇸 603 156 52ms 3 Jun 2025 676th MeWhenI 🇻🇦 597 164 7ms 1 Aug 2023 677th OllyTDev 595 85 17ms 22 Aug 2023 677th NickTheEASDude 🇺🇸 595 85 110ms 20 Aug 2024 679th AlephSquirrel 589 57 15ms 21 Jan 2025 680th Thinkr1 589 62 45ms 18 Nov 2025 680th KatieLG 🇬🇧 589 62 43ms 3 Feb 2026 682nd rustykitty 🇺🇸 588 86 18ms 31 Oct 2025 683rd CatsAreFluffy 587 86 47ms 2 Jan 2024 684th MeWhenI 🇻🇦 587 235 1,689ms 7 Nov 2025 685th madex 🇩🇪 583 168 12ms 21 Feb 2024 686th davbass 🇮🇹 582 66 213ms 25 Aug 2023 687th Chinay-Domitrix 🇺🇸 581 114 2,794ms 23 days ago 688th kmathis22 581 196 507ms 6 Dec 2025 689th edsrzf 🇳🇿 580 63 45ms 25 Dec 2025 690th RobertHoeh 574 88 208ms 16 May 2024 691st MeWhenI 🇻🇦 574 164 47ms 29 Apr 2025 692nd namelessiw 572 199 548ms 15 Nov 2025 693rd Zekaroni 568 89 18ms 29 Aug 2023 693rd CatsAreFluffy 568 89 190ms 2 Jan 2024 695th Yewzir 🇧🇪 565 244 297ms 3 Jan 2024 696th didion0 🇺🇸 561 90 15ms 24 Feb 2025 696th CaedenHarper 🇨🇦 561 90 192ms 6 Sep 2025 698th MeWhenI 🇻🇦 560 69 39ms 1 Aug 2023 699th MeWhenI 🇻🇦 558 172 410ms 15 Oct 2023 700th Mabeloid 🇳🇴 558 235 126ms 26 Oct 2025 701st MeWhenI 🇻🇦 557 224 6ms 12 Jan 2025 702nd dokutan 556 248 285ms 6 Jan 2024 703rd dokutan 554 237 123ms 11 Jan 2024 704th dokutan 554 240 235ms 1 Jul 2025 705th DialFrost 🇸🇬 553 177 5ms 11 Nov 2024 706th adamnielson42 🇺🇸 552 70 539ms 17 Nov 2023 707th CatsAreFluffy 543 89 594ms 15 Jan 2024 708th roguh 🇬🇹 543 93 17ms 9 Jan 2024 709th albanian-laundromat 542 205 2ms 25 Jun 2025 710th KaustubhDighe 538 94 17ms 3 Nov 2023 711th CaedenHarper 🇨🇦 538 165 1,011ms 19 Oct 2025 712th elgan65536 🇺🇸 536 245 119ms 7 Feb 2026 713th MeWhenI 🇻🇦 534 208 2ms 1 Aug 2023 713th m-tkach 🇺🇦 534 208 2ms 1 Aug 2023 713th dokutan 534 208 2ms 27 Mar 2024 716th alexeldridge 526 96 144ms 27 Aug 2024 717th CaedenHarper 🇨🇦 519 266 307ms 4 Nov 2025 718th Yewzir 🇧🇪 517 215 2ms 18 Jan 2024 719th Schmitt-Very-Cool 515 221 878ms 1 Oct 2025 720th dokutan 513 236 96ms 23 Jul 2025 First Prev 641–720 of 1,822 Next Last