I've read about it weeks ago and with my collective I'm gathering all the information I can. I think that is simple as it seems, a plexiglass square covering an LCD monitor surrounded by infrared LEDs, using the FTIR technique we can track multiple points on the sreen. Using libraries like JMyron for processing we can then capture those tracking points and make Processing draw something... Bartolomeus is the RESOLUME developer (resolume is a VJing software) and on its forum told that he could make sometinhg working with this kind of structure... very interesting topic