flowers growing out of shadow/shilloutte

hi,

following concept:

a user is crossing the lightbeam of a videoprojector and his/her shadow is appearing on the wall as a black shilloutte.

-> now i want to have a projection of some abstract black flowers growing around and out of the shilloute/shadow on the wall.

- how did i get the essential information of the shadow contour. what's a good angle and position of the camera and projector for doing this?
- how did i animate and programm the growing plants?

thanx for hints, tipps and links

greets
peter