In the late 1940s there was a physical model, water driven, of the British economy.  (How does the economy work? | Science Museum

www.google.com.au/?gfe_rd=cr&ei=BmCLVpfUE-jN8AesooCwAw).

This made me wonder if some of the methodologies I read about in SMO could be used, or are being used, to optimize (not sure what objectives would be!!) national economies.