Tower of Hanoi


In the great temple at Benares, beneath the dome which marks the centre of the world, rests a brass plate in which are fixed three diamond needles, each a cubit high and as thick as the body of a bee. On one of these needles, at the creation, God placed sixty-four discs of pure gold, the largest disc resting on the brass plate, and the others getting smaller and smaller up to the top one. This is the Tower of Bramah. Day and night unceasingly the priests transfer the discs from one diamond needle to another according to the fixed and immutable laws of Bramah, which require that the priest on duty must not move more than one disc at a time and that he must place this disc on a needle so that there is no smaller disc below it. When the sixty-four discs shall have been thus transferred from the needle on which at the creation God placed them to one of the other needles, tower, temple, and Bramahns alike will crumble into dust, and with a thunderclap the world will vanish.

Puzzle invented by Edouard Lucas in 1883. Story invented by Henri de Parville in 1884.


If the priests transfer 1 disc every second, all 64 discs will be transferred to the third needle in 2⁶⁴ - 1 seconds, which is more than 580 billion years.



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