The History of the Sliding Puzzle
A box of numbered tiles and one empty place: in 1880 the sliding puzzle was a craze in the United States.
Canastota, New York
The sliding puzzle is generally credited to Noyes Palmer Chapman, a postmaster in Canastota, New York, who is said to have shown friends a forerunner as early as 1874. In 1880 the puzzle with fifteen tiles became a craze in the United States; Chapman applied for a patent that February, and it was refused.
A claim without proof
The puzzle writer Sam Loyd claimed from 1891 until his death in 1911 that he had invented it. There is no evidence for this: he had nothing to do with its invention or its first popularity.
Half cannot be solved
As early as 1879 the mathematicians W. W. Johnson and W. E. Story showed that only half of all ways to put the tiles into the box can be solved - the rest can never be put in order. That is why PaperGames mixes every puzzle with real moves.