Numero

Numero (aka 15-puzzle) is a sliding puzzle that consists of a 4x4 grid of numbered square tiles in random order with one tile missing.
The object of the puzzle is to place the tiles in order from 1 to 15 by making sliding moves that utilise the empty space.
Back in the 1950s in Melbourne, Australia, an inventor named Mr. Richard took the old 1870s wooden sliding blocks game, 15-puzzle, and transformed it into a new craze by creating sliding tiles in a thin hard plastic case.
Selling the puzzle, named Numero, from his shop in Elizabeth Street, he quickly made his fortune but, like other puzzle inventors to follow, he failed to take out a Patent on his invention.
As a result, the puzzle became mass-produced overseas until the craze eventually died down.
Mr. Richard's son related the story to me and asked if I could make him an Android version of the puzzle.
So, here it is. Numero, in its original basic form. A tribute from me to the Richard family.
Enjoy!