2026-06-16 · history
The 15 Puzzle (1880) — The Unsolvable Move with Which Sam Loyd Fooled the World
In early 1880 a craze for the '15 Puzzle' swept America and Europe. But Sam Loyd, whom the world believed to be its inventor, was an impostor who only claimed authorship sixteen years after the craze had ended. This essay traces the box's true origin and the 1879 proof that the 'swapped 14-and-15' board Loyd staked his prize on is mathematically unsolvable, and rereads the legacy sliding puzzles left to modern digital puzzle design: the guarantee of solvability.