“The original design made it hard to understand where you were supposed to go, either entering or leaving,” Mitchell told The New York Times. “Traffic diagrams showed a huge amount of path-crossing. I started to think it would be fabulous to eliminate all this crisscrossing and straight edges, which cause anxiety when they go on too long. David asked me what dance patterns I would use, and I said, ‘People move easiest in circles: off and on the merry-go-round.’ “
Full story and slide show in The Times.