puzzle
This is a 3D-printable 15-puzzle. It includes a board, a piece, and a small piece model. The board should be printed once. The piece can be printed 14 times, and then the small piece once. The pieces pop into the board and are held in by each other. The small piece is meant to be put in last; it is only slightly smaller, but a regular piece is difficult to fit in after 14 other pieces are inserted.
The pieces themselves are blank. This way, you can cut out and tape pictures to each piece, or you can simply draw numbers or letters on them with a marker.
Renderings
Rendering of the board itself:
Rendering of a piece: