Sliding-block Puzzles

The December issue of The Economist contains an article with a prominent question. Has an inventor found the hardest possible simple sliding-block puzzle? It goes on to describe the Quzzle puzzle, by Jim Lewis. The article finishes with "Mr Lewis claims that Quzzle, as he dubs his invention, is 'the world's hardest simple sliding-block puzzle.' Within the terms of his particular definition of 'simple,' he would seem to have succeeded."

Read more: