Eternity puzzle

Eternity is a tiling puzzle created by Christopher Monckton and launched by the Ertl Company in June 1999. Consisting of 209 pieces, it was marketed as being practically unsolveable, with a £1 million prize on offer for whoever could solve it within four years. The prize was paid out in October 2000 for a winning solution arrived at by two mathematicians from Cambridge. A second puzzle, Eternity II, was launched in Summer 2007 with a prize of US$2 million.

The puzzle's scope was to fill a large almost regular dodecagon with 209 irregularly shaped smaller polygon pieces of the same color. All the pieces were made from a combination of equilateral triangles and half-triangles, with each piece having the same total area of 6 of those triangles, and between seven and eleven sides.

The puzzle was launched in June 1999, by Ertl, marketed to puzzle enthusiasts and 500,000 copies were sold worldwide, with the game becoming a craze at one point. Eternity was the best-selling puzzle or game in the UK at its price-point of £35 in the month it was launched.

The puzzle's inventor Christopher Monckton put up half the prize money himself, the other half being put up by underwriters in the London insurance market. According to Eternity's rules, possible solutions to the puzzle would be received by mail on September 21, 2000. If no correct solutions were opened, the mail for the next year would be kept until September 30, 2001, the process being repeated every year until 2003, after which no entries would be accepted.

Before marketing the puzzle, Monckton had thought that it would take at least three years before anyone could crack the puzzle. One estimate made at the time stated that the puzzle had 10⁵⁰⁰ possible attempts at a solution, and it would take longer than the lifetime of the Universe to calculate all of them even if you had a million computers.

Once solved, Monckton claimed that the earlier-than-expected solution had forced him to sell his 67-room house, Crimonmogate, to pay the prize. In 2006, he said that the claim had been a PR stunt to boost sales over Christmas, that the house's sale was unrelated to the prize as he was going to sell it anyway.

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Wikipedia