After the inventor of chess had demonstrated his new game to a king in India, the king was suitably impressed and asked the inventor to name his reward. The inventor replied that his wishes were simple – he only asked for one grain of rice for the first square of the chessboard, two grains for the next square, four for the next, eight for the next and so on for all 64 squares, with each square having double the number of grains as the square before. Pleasantly surprised at the seemingly modest request, the king instructed his treasurer to pay out the reward. A week later, the treasurer informed the king that the reward was greater than the resources of the entire kingdom. In fact, the reward worked out to a total of approximately 18,446,744,073,709,600,000 grains of rice or over 350 billion metric tons of rice (assuming 50 grains of rice per gram). To put this in perspective, 500 million metric tons of rice is consumed globally every year, the reward was 700 times that. At ~US$1 per kg of rice*, in value terms the reward would be worth over US$350 trillion or ~120 times India's GDP^!

* Based on price data from Agriwatch.com for 1 kg of rice in Karnal, Haryana, as on March 27, 2019; ^ Based on IMF estimate for 2018 GDP.