When I used to commute via mass transit, my train load of people would all rush down the platform, into a plaza, and down only one escalator. You had people wh

When I used to commute via mass transit, my train load of people would all rush down the platform, into a plaza, and down only one escalator. You had people who would rush forward, people who would take a steady pace, and people who would hang back. I often times looked at the flow of people and it seemed to me it was extremely similar to a flow of particles.