What is the Tower of Hanoi?

The Tower of Hanoi is a mathematical puzzle, invented by French Mathematician Edouard Lucas in 1983.

Object of the game:

There are three rods or towers, and on the first rod or tower is a stack of discs of different sizes arranged in the decreasing order of size from bottom to top. The object of the game is to move all of the discs to the third rod and arrange them in the same order. However, only one disc can be moved at a time, and a larger disc cannot be placed on top of a smaller disc.

How to play:

If you have 3 discs, a  total of 7 moves will be required.

Move 1:  Move the topmost disc from rod A to rod C

Move 2:  Move the second disc from rod A to rod B

Move 3:  Move the disc from rod C to rod B.

Move 4:  Move the last disc from rod A to rod C.

Move 5:  Move the top disc from rod B to rod A.

Move 6:  Move the remaining disc from rod B to rod C.

Move 7:  Move the disc from rod A to rod C.

The number of moves increases the number of discs. For eg. with 4 discs, a total of 15 moves will be required.

Applications: The game is frequently used in psychological research and teaching recursive algorithms in computer programming.