Picture Swap

Picture Swap is a gentle jigsaw-style puzzle. A picture of mountains, pine trees, a lake and a small sailing boat has been cut into a 4×4 grid, and the tiles have been shuffled.

Tap one tile and then another to swap them. A green corner appears on every tile that is in its correct place, so you can see the picture coming together. There is no timer; the challenge is to finish in as few swaps as you can. A perfect player never needs more than fifteen, and each swap that puts two tiles home at once saves a move.

Swap tiles until the whole picture is in order. Your score is the number of swaps used — fewer is better.