Virtual physics circus.

This video shows the Virtual Physics Circus, a kind of playground for experimenting with simple physical models. The system makes it easy to create worlds with common physical objects such as swings, vehicles, ramps, and walls, and interactively play with those worlds. The system can be used as a creative art medium as well as to gain understanding and intuition about physical systems. The system can be controlled by a number of UI devices such as mouse, keyboard, joystick, and tags which are tracked in 6 degrees of freedom.