Many hundreds of years ago a traveller introduced the game of chess to a wealthy Indian king. The king was so pleased that he asked the traveller to name a reward.

The traveller said ‘All I ask for is some rice. Just one grain on the first square of the chess board, two on the second, four on the third and so on, for all the squares on the board’.

The king, thought this was a modest request and quickly granted it.

However, the king soon realised that there was not enough rice in his entire kingdom, or even the world, to meet the agreed reward.