توضیحات:

The Game of Fifteen (also called 15 puzzle, Gem Puzzle, Boss Puzzle, Mystic Square and many others) is a sliding puzzle that consists of a frame of numbered square tiles in random order with one tile missing.
The puzzle also exists in other sizes, particularly the smaller 8-puzzle.

The object of the puzzle is to place the tiles in order from first to last tile by moving the tile next to the empty space into it.