The Tower of Hanoi

There is a legend about an Hindu temple which contains a large room with three time-worn posts. The priests in the temple were given a stack of 64 gold disks, each one a little smaller than the one beneath it. The priests of Brahma, acting out the command of an ancient prophecy, have been moving these disks, in accordance with the rules of the puzzle

- a large disk could never be placed on top of a smaller one
- only one disk could be moved at a time

According to the legend, when the last move of the puzzle is completed, the temple would crumble into dust and the world would vanish.

If the priests worked day and night, making one move every second it would take slightly more than (2^64)−1 seconds or 580 billion years to accomplish the job.

Unfortunately, the universe is currently about 13.7 billion years old only.