“This is what I call the Box 2D mothership over here," Catti says, indicating toward a computer where, with a few quick keystrokes, he calls up a virtual world in which he is the master of gravity, friction, momentum.“I’ve always been interested in the way things move in Angry Birds T Shirts the real world that we see, like, why does it move like that? Why does it slide like that? And why does it tumble? So I have always wanted to explore that and recreate that.”

You can apply the Box 2D code to any video game to give it real world physics in two dimensions. Sounds like an obvious feature, but let’s take a quick trip back through video game history.In the early days, games were full of flimsy physics. Just think of Super Mario. “Mario can stop in a dime. He can do a 180. He can actually change his direction in the air. But you know if you jump, you can’t reverse and go backwards.”