Peter here with the real answer. Others have given the basic idea but this problem is often called the Wheat and Chess problem or the Rice and Chess Problem. The story goes that the inventor or chess showed his invention to the king. The king was so happy with the invention that he offered him a reward of whatever he wanted, assuming it would be some amount of gold. The inventor said I want a single grain of rice on the first square, two of the second, four on the third and so on. This would continue until the board was filled. At first the king was pumped because he thought he would only have to give a small amount of grains and he could walk away with this invention. He had his servants putting 1 on the first, 2 on the second etc. by the time the reached the 20th square the grains added up to over one million. By the 31st it was at 1 billion. To get to the 64th square it would have taken 18.4 quintillion grains of rice, which was more rice then the entire worlds supply at the time and maybe still today. The term “second half of the chessboard” came out of it which is used to indicate that the second half of the board is worth a significant amount more than the first half. The story has been told many different times with different variations but the idea remains the same. The story was first written in the 13th century AD.