What it is

Sort Quick is our take on the 15-puzzle, an 1880s pocket toy that became briefly responsible for a public craze comparable to Rubik's Cube. Fifteen numbered tiles fit in a 4×4 grid with one tile-sized empty space. Tiles adjacent to the empty space can slide into it. Your job: starting from a shuffled state, slide tiles around until the numbers read 1, 2, 3, 4 across the first row, 5, 6, 7, 8 across the second, and so on — with the empty space ending at the bottom-right.

How to play

Click or tap a tile. If it's adjacent to the empty space, it slides in.
You can slide a row of tiles at once in some versions — but in this one, one tile per move, by design.
Solve the puzzle. 1-15 in order, empty at bottom-right.
Best is measured in moves. A fresh puzzle is solvable in roughly 60-80 moves with good play. Skilled players hit 50.

The trick

The 15-puzzle has a known solving pattern: solve the top row first, then the left column, then reduce to a 3×3 subproblem, then to a 2×2. Trying to solve "the next-easiest tile" usually creates conflicts later. The most important trick at the top row is to place tile 4 before tile 3 — you put 3 in the position where 4 should be, then rotate them both in. This avoids the most common "I need to undo half my work" deadlock for beginners. Players who learn this technique drop from 200+ moves to under 100 in a few sessions.

What this scored well on

The puzzle is famous. Most players have seen it; few have actually solved one. The combination of "recognised" and "novel-feeling-when-completed" makes a strong package.
Honest shuffling. Our shuffle is guaranteed solvable (you can build unsolvable configurations of the 15-puzzle, but you have to do it deliberately). We perform many random valid moves from the solved state, which never produces unsolvable boards.
Light visual. Numbers, not images. Image-based 15-puzzles are pleasant but obscure the actual puzzle for new players.

What it gets wrong

Sort Quick rewards players who have learned the standard solving pattern much more than it rewards casual play. There's no "easy mode" and the difficulty floor is high — a player with no exposure to this puzzle might spend 300-500 moves on their first solve. We considered adding a hint mode (showing the next correct move) but decided it would defeat the puzzle. If you find yourself stuck for more than fifteen minutes, the right move is to look up "how to solve the 15-puzzle" — your second run will be a completely different experience.

Who it's for

Sort Quick is for players who like the long-arc satisfaction of "I learned a system" — once you internalise the corner-first method, the puzzle stops being a puzzle and becomes a small piece of muscle memory. It's also a useful introduction to algorithmic thinking, in the same family as solving Rubik's Cube via the layer-by-layer method.

Where we'd point you next

If you liked the puzzle-solving rhythm, try Code Crack (#11 — pure deduction). If you liked the sliding tile feel, watch for variants in future issues.

Released · 12 May 2026 · Editor's score 3.9 / 5 · Reviewed by Bill