[SoulKiss]

Heres how it works

Here is the same video as on youtube, but clearer -

http://mtg.upf.edu/reactable/videos/demo2_basic1.mp4

And 2 others

http://mtg.upf.edu/reactable/videos/demo2_basic2.mp4

http://mtg.upf.edu/reactable/videos/demo2_improv.mp4

Much more info on the website tho

In summary tho its a camera/projector setup to monitor whats on the table and provide visual feedback

David