Ever got a dollar bill stamped with a Where's George stamp? It's a fun game to most people, where they can enter a banknote's serial number to track where it has been, but to theoretical physicist Dirk Brockman, they represent data on money - and therefore human - mobility.
In 2006, after crunching the data, Brockman came up with a completely different map of the United States, where states' geographic boundaries melt away and are replaced with financial ones. Here's the map he created when he, well, followed the money:
Theoretical physicist Dirk Brockmann used the dollar bill tracking site Where’s George to see how money moves, and create new state boundaries based on our economies. The darker the blue lines, the less likely it is a dollar bill will have crossed it.
Read more over at this article by Stan Alcorn over at Co.Exist: Link