The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 7 days. Why not try and solve them ahead of time?
Jacobi Symbol 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 481st emgordon154 566 374 1,673ms 21 Dec 2025 482nd alphafalfa 564 110 6ms 25 Oct 2024 483rd Schmitt-Very-Cool 563 252 488ms 30 Sep 2025 484th SirBogman 🇺🇸 562 135 511ms 16 Jan 2024 485th yzhs 🇩🇪 562 144 18ms 31 May 2022 486th GrayJoKing 🇦🇺 561 126 155ms 24 Oct 2024 486th rucin93 🇵🇱 561 126 154ms 3 Jan 2025 488th bac0id 561 223 404ms 29 Jun 2024 489th Lv0Sys 🇵🇱 560 148 15ms 25 days ago 490th bac0id 560 191 115ms 29 Jun 2024 491st the-zammers 560 222 146ms 15 Oct 2023 492nd MeWhenI 🇻🇦 557 157 1,032ms 23 Jun 2024 493rd JOrE20 556 149 11ms 24 Dec 2025 494th MeWhenI 🇻🇦 555 141 264ms 23 Jun 2024 495th Command-Master 555 146 17ms 29 Sep 2023 496th SirBogman 🇺🇸 554 86 34ms 9 Jan 2023 497th tatzyr 🇯🇵 554 94 38ms 24 Nov 2024 498th 386asm 🇺🇸 554 214 37ms 4 May 2023 499th Shanethegamer 🇺🇸 553 283 230ms 11 May 2022 500th MeWhenI 🇻🇦 552 137 317ms 29 Jan 2023 501st lifthrasiir 🇰🇷 551 85 4ms 27 Nov 2024 502nd bricknellj 551 147 10ms 24 Jun 2024 503rd madeforlosers 549 151 10ms 23 Oct 2024 503rd tomh1012 549 151 27ms 12 days ago 505th jacobly0 🇺🇸 548 192 2ms 13 Sep 2023 506th retrohun 547 148 12ms 21 May 2022 506th argusdusty 🇺🇸 547 148 17ms 21 Aug 2022 508th bac0id 545 260 412ms 29 Jun 2024 509th MeWhenI 🇻🇦 544 218 39ms 23 Jun 2024 510th levikeck 543 229 145ms 5 Feb 2024 511th DialFrost 🇸🇬 542 96 36ms 5 Jan 2023 511th olivermrose 🇺🇸 542 96 37ms 21 Jan 2023 511th olleicua 🇺🇸 542 96 37ms 15 Feb 2025 514th MeWhenI 🇻🇦 541 117 9ms 23 Jun 2024 515th stefangimmillaro 540 150 10ms 19 Sep 2023 515th stertooy 🇧🇪 540 150 31ms 15 Jun 2024 515th InigoK 🇺🇸 540 150 18ms 25 Aug 2025 518th weliveinhell 🇭🇹 540 199 2ms 21 May 2024 519th KatieLG 🇬🇧 540 232 390ms 13 Oct 2024 520th Bubbler-4 539 87 18ms 9 May 2022 521st MeWhenI 🇻🇦 539 115 2ms 11 Nov 2022 522nd dokutan 539 219 298ms 24 Mar 2025 523rd MeWhenI 🇻🇦 538 141 615ms 24 May 2024 524th sisyphus-ppcg 🇦🇺 536 97 35ms 27 Dec 2023 525th KasperKivimaeki 🇫🇮 536 151 17ms 17 Dec 2025 526th Yewzir 🇧🇪 536 191 2ms 7 May 2024 527th 2bular 535 89 33ms 30 Jan 2026 528th Alessandro-Balconi 🇮🇹 534 183 117ms 15 May 2023 529th brimstonetrader 534 233 143ms 20 Mar 2024 530th NewDefectus 🇮🇱 533 152 10ms 10 May 2022 530th TaserTheFox 🇺🇸 533 152 17ms 26 May 2023 530th Lv0Sys 🇵🇱 533 152 11ms 25 days ago 533rd HumanoidCPU 531 248 370ms 8 Aug 2024 534th DialFrost 🇸🇬 529 143 301ms 16 Jun 2024 535th janbehrens 🇩🇪 529 153 31ms 17 Jun 2023 536th helbling 🇨🇭 528 157 10ms 3 Oct 2024 537th qpwoeirut 526 154 11ms 2 Oct 2025 537th CaedenHarper 🇨🇦 526 154 32ms 6 Nov 2025 539th CaedenHarper 🇨🇦 524 145 516ms 6 Nov 2025 540th emgordon154 524 205 2ms 28 Dec 2024 541st janbehrens 🇩🇪 522 126 3ms 22 May 2022 542nd YAJUE114514 522 155 10ms 15 Aug 2025 543rd yzhs 🇩🇪 520 241 392ms 5 Jun 2022 544th The3gs 520 301 190ms 28 Nov 2024 545th Yewzir 🇧🇪 517 208 2ms 10 Jun 2024 546th CedricGebistorf 516 157 11ms 5 May 2023 547th alemelis 515 152 288ms 22 Sep 2024 548th msbranicky 515 199 2ms 13 Oct 2023 549th error256 513 215 73ms 21 May 2025 550th Just4FunCoder 512 158 17ms 26 Mar 2023 551st msbranicky 511 304 2ms 12 Aug 2023 552nd guilhem-roy 🇫🇷 509 159 18ms 9 May 2022 552nd OllieBoyne 🇬🇧 509 159 10ms 13 May 2022 552nd TobyBoyne 🇬🇧 509 159 10ms 13 May 2022 555th MeWhenI 🇻🇦 507 309 237ms 25 May 2022 556th scpchicken 🇵🇼 506 130 6ms 29 Dec 2022 557th nstearns96 🇬🇧 506 160 10ms 15 Dec 2022 557th ahmetdemirag 🇨🇾 506 160 18ms 6 Mar 2025 559th Jacob385 505 281 487ms 1 Feb 2025 560th bizy-coder 503 151 503ms 27 Nov 2025 First Prev 481–560 of 726 Next Last