The arcade
77 short challenges across 9 categories.
- ✊ Rock Paper Scissors referee
- 🪢 Hangman display
- ❌ Tic-tac-toe winner
- 🎲 Yahtzee scorer
- 🃏 Blackjack hand value
- 🟩 Wordle feedback
- 🦠 Conway's Game of Life step
- 🌀 Maze solver (BFS)
- 🚗 VIN decoder
- 💳 Card number checker (Luhn)
- 📡 Morse code decoder
- 🚘 UK number plate age
- 🏷️ Barcode check digit (EAN-13)
- 📚 ISBN-10 validator
- 🗝️ Crack the Caesar cipher
- 🔢 Binary and hex decoder
- 🏛️ Roman numerals to numbers
- 📮 UK postcode parser
- 🎙️ NATO phonetic spelling
- 🥤 Vending machine
- 🛒 Supermarket checkout
- 🏧 ATM note dispenser
- 🪙 Till change maker
- 🅿️ Car park charge
- 🛗 Lift controller
- 🚦 Traffic light state machine
- ☕ Coffee machine resources
- 🧩 Unscramble: FizzBuzz
- 🧩 Unscramble: binary search
- 🧩 Unscramble: bubble sort
- 🧩 Unscramble: write then read a file
- 🧩 Unscramble: a class with a method
- 🧩 Unscramble: Fibonacci generator
- 🐛 Bug: the missing last number
- 🐛 Bug: assignment vs comparison
- 🐛 Bug: text plus number
- 🐛 Bug: the sticky default list
- 🐛 Bug: the list that changed itself
- 🐛 Bug: the counter that never counts
- 🐛 Bug: 0.1 + 0.2
- 🐛 Bug: off the end
- 🔴 Connect Four judge
- 💣 Minesweeper numbers
- 🃏 Poker hand ranker
- 🎯 Darts two-dart checkout
- 🐍 Snake engine
- 🔤 Scrabble scorer
- 🔢 2048 row merge
- ♞ Knight shortest path
- 🏦 IBAN validator
- 🏥 NHS number checksum
- ⏱️ Unix timestamp decoder
- 🌐 Subnet calculator
- 🧬 Base64 by hand
- 🧺 Washing machine cycle
- ⛽ Petrol pump
- 🌡️ Smart thermostat
- 🚉 Ticket barrier
- 🧽 Deduplicate a contact list
- 🔀 Pivot a sales table
- 🔗 Join two tables
- 🕳️ Fill the gaps
- 📦 Run-length codec
- ⚖️ Bracket balancer
- 📆 Merge overlapping bookings
- 🍬 Trick-or-treat tally
- 🎃 Share the sweets fairly
- 👻 Spooky name generator
- 🛒 Pumpkin patch pricing
- 🧙 The witch’s note
- 🏚️ Escape the haunted house
- 🛌 Sleeps till Christmas
- 🎄 Draw the Christmas tree
- 🎁 Wrapping paper calculator
- 🛍️ Presents on a budget
- 📜 Naughty or nice list
- 🛷 Pack Santa's sleigh