Game of 15

The puzzle was "invented" by Noyes Palmer Chapman, a postmaster in Canastota, New York, who is said to have shown friends, as early as 1874, a precursor puzzle consisting of 16 numbered blocks that were to be put together in rows of four, each summing to 34 (Wikipedia). And see what it has come to now! It is popularly played by all age groups! The puzzle can be extended to a board size of any dimension but as of the app supports the classic 4x4 16-tiled version. Keep watching this space for improvements and enhancements. Mission: Rearrange the tiles until they go from 1 through 15 in left to right order in as less moves as possible.