The Gray Code Decoder and Gray Code Encoder holes will go live in approximately 40 hours. Why not try and solve them ahead of time?
PalindromemordnilaP in all languages in bytes. 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 Bytes Time Submitted 401st stefangimmillaro 778 114 396ms 4 Sep 2024 402nd MeWhenI 🇻🇦 777 39 33ms 2 Sep 2024 403rd the-zammers 775 114 117ms 1 Dec 2024 404th snoozingnewt 🇨🇦 774 82 486ms 22 Nov 2025 404th dokutan 774 82 414ms 27 Feb 2026 406th jatloe 774 99 11ms 4 Sep 2024 406th alexeldridge 774 99 11ms 14 Sep 2024 406th Just4FunCoder 774 99 10ms 14 Sep 2025 406th 0xjac 🇨🇭 774 99 9ms 24 Nov 2025 410th dokutan 773 104 203ms 1 Sep 2024 411th error256 769 139 504ms 24 Sep 2024 412th emgordon154 769 156 404ms 4 Mar 2025 413th edsrzf 🇳🇿 767 83 106ms 28 Feb 2026 414th Kacarott 🇦🇺 766 100 9ms 3 Sep 2024 414th Artemis21 🇬🇧 766 100 11ms 4 Jan 2025 416th lifthrasiir 🇰🇷 765 83 431ms 2 Dec 2024 416th albanian-laundromat 765 83 461ms 4 Aug 2025 416th CaedenHarper 🇨🇦 765 83 494ms 9 Aug 2025 419th CatsAreFluffy 763 64 49ms 4 Nov 2024 420th error256 762 116 122ms 2 Sep 2024 421st madex 🇩🇪 758 101 10ms 1 Sep 2024 421st RedzGoose 🇦🇺 758 101 10ms 15 Oct 2024 421st JunkIce 758 101 10ms 25 Oct 2024 424th targrik 756 83 5ms 8 Feb 2025 425th Shanethegamer 🇺🇸 755 117 119ms 1 Sep 2024 426th sean-niemann 🇺🇸 755 118 3ms 16 Jan 2025 427th stefangimmillaro 754 94 9ms 4 Sep 2024 428th sciencejiho 751 102 9ms 13 Sep 2024 428th Papushkado 751 102 10ms 10 Nov 2025 428th TheSecondComing123 751 102 10ms 4 Feb 2026 431st DialFrost 🇸🇬 751 225 1,563ms 20 Jan 2025 432nd UnderKoen 🇳🇱 750 185 63ms 1 Dec 2025 433rd kg583 🇺🇸 749 102 5ms 19 Dec 2025 434th error256 748 226 1,433ms 28 Mar 2025 435th Shanethegamer 🇺🇸 746 95 10ms 1 Sep 2024 435th HumanoidCPU 746 95 10ms 29 Oct 2024 437th Mikey-Beep 🇬🇧 745 119 404ms 2 Sep 2024 438th julian-hoelz 744 103 10ms 16 Sep 2024 438th StefanHabel 🇨🇦 744 103 90ms 22 Mar 2025 440th pardouin 🇫🇷 741 87 77ms 3 Sep 2024 440th Steffan153 🇫🇮 741 87 81ms 11 Feb 2026 442nd xsot 🇸🇬 739 58 1,009ms 19 Dec 2025 443rd stefangimmillaro 739 169 43ms 3 Sep 2024 444th Shanethegamer 🇺🇸 737 71 233ms 1 Sep 2024 444th MarcMush 🇫🇷 737 71 536ms 16 Sep 2024 446th ComputerKWasTaken 🇺🇸 736 104 10ms 2 Sep 2024 446th elgan65536 🇺🇸 736 104 9ms 23 Sep 2024 446th NickTheEASDude 🇺🇸 736 104 10ms 7 Oct 2025 449th FlyingPenguin223 734 94 1ms 18 Sep 2024 450th DialFrost 🇸🇬 734 271 1,620ms 17 Jan 2026 451st GolfingSuccess 🇬🇷 733 30 53ms 1 Sep 2024 451st MeWhenI 🇻🇦 733 30 72ms 8 Jun 2025 451st CaedenHarper 🇨🇦 733 30 46ms 1 Dec 2025 454th error256 733 121 385ms 24 Sep 2024 455th snoozingnewt 🇨🇦 731 110 83ms 22 Nov 2025 456th targrik 730 97 10ms 8 Feb 2025 457th Shanethegamer 🇺🇸 729 122 6ms 4 Oct 2024 458th Shanethegamer 🇺🇸 728 105 4ms 1 Sep 2024 459th Shanethegamer 🇺🇸 728 128 473ms 1 Sep 2024 460th albanian-laundromat 728 232 1,433ms 15 Oct 2025 461st emgordon154 726 63 1,252ms 18 Nov 2024 462nd bitsandbeyond 🇳🇱 726 64 320ms 1 Dec 2025 463rd Shanethegamer 🇺🇸 726 95 2ms 2 Sep 2024 464th CutSandstone 722 106 12ms 21 Dec 2024 465th janAkali 🇷🇺 722 112 375ms 12 Feb 2026 466th GrayJoKing 🇦🇺 720 86 154ms 2 Sep 2024 467th kg583 🇺🇸 719 106 6ms 26 Sep 2025 468th dokutan 719 124 2ms 5 Sep 2024 469th Kacarott 🇦🇺 717 132 3ms 4 Sep 2024 470th galloj 🇨🇿 716 107 10ms 4 Sep 2024 470th FlorianCassayre 🇫🇷 716 107 10ms 9 Sep 2024 470th jared-hughes 716 107 10ms 10 Sep 2024 470th nstearns96 🇬🇧 716 107 9ms 13 Nov 2024 470th rchalamala 716 107 10ms 2 Jan 2025 470th brochmann 🇸🇪 716 107 9ms 16 Oct 2025 476th mykytamatiukha 714 168 221ms 15 Jan 2026 477th snyderek 🇺🇸 712 150 63ms 15 Sep 2024 478th JesseNoEyes 🇺🇸 709 108 10ms 30 Sep 2024 479th Shanethegamer 🇺🇸 709 114 104ms 2 Sep 2024 480th alexsave 708 100 10ms 22 Sep 2024 First Prev 401–480 of 770 Next Last