Quesnay’s model does more than present end-of-year results – it also shows how money and goods circulate through the year, and demonstrates why this is so important. The sale of products between the various groups continues to generate revenue, which produces yet more revenue. A “multiplier effect” occurs (in Quesnay’s scheme it appeared as a zig-zag series of lines), similar to that presented by John Maynard Keynes in the 1930s, when he pointed out the beneficial knock-on effects of government spending in a depressed economy.