Romer notes that business keeps evolving as new companies introduce new rule sets. The good ideas are copied, and workers migrate from failing companies to the new and old ones where the new rules are working well. The same goes for countries. Starting about 1970, China took some of the effective rules of Hong Kong (which was managed from afar by England) and set up four special economic zones along the coast operating as imitation Hong Kongs. They worked so well that China rolled out the scheme for the whole country, and its Gross Domestic Product took off. “Hong Kong was the most successful economic development program in history.