Ben writes in with this interesting experiment in body control –

The project “no strings: recursive” has drawn inspiration from the mouse-based turntable interfaces that you blogged a while back. In this work arms and legs are used to control the mouse pointers of two separate computers allowing me to write (or draw)two different things simultaneous. And yes the belt that turns the little wheel in the roller-ball mouse is dental floss.

This makes the traditional etch-a-sketch look easy by comparison. – No Strings