The fable explains how a Persian vizier once asked his sultan if he could be paid in grains of rice, such that there was 1 grain on the first square of a chessboard, then 2 on the second square, then 4, 8,16, and so on. The sultan agreed, thinking that the final amount of rice would be trifling, but in fact he was bankrupted because the final square of the chessboard contained 9,223,372,036,854,775,808 grains. The combined total for all the squares would have been almost twice this number, which far outstrips today’s worldwide annual production of rice.