Your own photo, cut up in the page
Choose a picture and it becomes the puzzle. It is cropped square, scaled down and sliced by this page, on your device — the file is never uploaded, and you can check that by turning the network off before you pick it.
A photo makes the puzzle much harder than numbers, because a piece of sky looks like every other piece of sky. Leave the small numbers on the pieces for a version that is merely difficult, or turn them off for one that is genuinely unpleasant.
Every shuffle can be solved
Half of all the arrangements of a 4×4 sliding puzzle cannot be solved at all. Shuffling the pieces at random therefore hands you an impossible puzzle about half the time — one that looks and plays exactly like a solvable one, right up until it does not finish.
So the board here is not shuffled. It starts solved and the gap is walked around it a few hundred times, which cannot leave a position you could not walk back from. Every board you are given has an answer.
Sizes and what counts as good
3×3 is a warm-up and can be solved in under thirty moves once you know the method. 4×4 — the classic fifteen puzzle — takes most people two or three hundred moves the first time and around eighty once they solve it row by row instead of piece by piece. 5×5 is for people who enjoyed 4×4.
The score kept is moves, per size.
Nothing is stored beyond the best move count per size, in this browser. A photo you choose is read, cropped and cut up by the page, and is never written anywhere or sent anywhere.
Switch the network off and pick a photo if you would like to see that for yourself — the puzzle behaves identically.
Frequently asked questions
Is my photo uploaded anywhere?
No. It is read by the page, cropped and sliced by your own browser, and never sent. Disconnect from the network first if you would like to prove it — the puzzle works exactly the same.
How do I actually solve it?
Row by row from the top, and column by column from the left, finishing each one before you disturb it. The last two rows are the part that needs a trick, because placing the final two pieces of a row means temporarily unplacing them.
Can a shuffle be impossible?
Not here. The board is produced by walking the gap around a solved puzzle, so a route back always exists. Puzzles that shuffle at random without checking are the reason this question gets asked.
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