There are a bazillion things you can do with webcam and a projector. One I just thought of is taking bounding boxes around people laying on the floor as an affine transformation and then generating an IFS. Three people will give you some variant of the Serpinski triangle; four properly arranged will give you Barnsley's fern. One thing I'd like to try with a projector is to put multiple cameras in an arc in front of a rough surface covered in glitter illuminated by a digital projector. Then one can determine which projector pixels reflect into which camera pixels; it ought to give a cheap 3d display (though I can't vouch for the quality). Puzzle games like Block and Roll are a fun model of certain finite axiomatic systems, where the initial board layout encodes the set of axioms, each game position is a theorem, each move is a rule, and you're trying to prove a specific theorem. -- Mike Stay - metaweta@gmail.com http://www.cs.auckland.ac.nz/~mike http://reperiendi.wordpress.com