Also...

The below post has come from failed attempts with a similar concept, except this was software found from a website called www.graffitiresearchlab.com, the software was called laser tag, here a webcam picks up the point of a laser on a surface, and then as this is connected to a projector it then creates a digital image drawn from moving the laser in a certain way.

I attempted to try this with my tutor Simon Gordon, but unfortunately we could not figure out how to get it to work, using a macbook and connecting the webcam it did not seem to respond.