Speedrun
For iPhone

Slide Puzzle Speedrun

The 4x4 fifteen puzzle, built for speed. Fair scrambles, an optimal solver that grades every board, and a 120 Hz board that keeps up with your fingers.

Today's board
10.46 trillionsolvable positions, every one equally likely in a scramble
Exactdifficulty for every board, from the optimal solution
120 HzMetal board with tap, swipe and hover controls
1 dailyboard a day, the same for every player
A look inside

Fast to read. Fast to play.

Every screen stays out of the way of the board. Colors show the layer each tile belongs to, so a misplaced tile is easy to see.

The home screen with the four modes
Pick a mode
A solve in progress with the timer above the board
Solve against the clock
A replay beside the optimal solution, with a chart of moves to solved
Replay beside optimal
A Blind solve with the numbers hidden
Go blind
Statistics with averages and a history chart
Track every average
Features

Everything a speedsolver needs.

Random-state scrambles

Each scramble is a uniform draw from all 16!/2 solvable positions, not a short random walk. The solver labels each board with its exact optimal length and how it ranks against every other position.

Optimal solver and replays

An IDA* search with a 6-6-3 pattern database finds the shortest solution on the phone. Replay any solve beside the optimal path, with your efficiency, your wasted moves, and a chart of moves to solved.

WCA-style stats

Single, mo3, ao5, ao12, ao50, ao100 and ao1000 with the standard trim. Personal bests, streaks, a history chart, and CSV or JSON export.

Game Center

Leaderboards for single, ao5, ao12, fewest moves, and TPS, plus achievements. Before a Standard solve posts, the app replays its move log from the scramble and checks the time and the move count.

120 Hz Metal board

The board draws with Metal at up to 120 Hz on ProMotion screens. Pick Tap, Swipe, or Hover controls. With Hover, tiles slide as your finger passes over them.

Share a replay

Send a solve as a link. It opens in the app, or plays right here in the browser for friends who do not have the app yet.

Four ways to play

StandardOne scramble, one time. The classic event.
MarathonSeveral boards in a row on one clock.
BlindInspect, then the numbers go away. Peek if you must.
DailyOne shared board a day, the same for everyone.
Daily

Today's board is ready.

Everybody gets the same scramble. It changes at midnight UTC.

See today's board