In trying to find articles and artworks that would help me conceptualize what I read in Casey Reas's article "Programming Media", I came across an artist/programmer named Daniel F. Keefe.
Here is a video of a program he is working on called 'Cave Painting'.
This is an example of how a program can be told to read gestures, and then it translates them. I think that in the Reas article, the particular program he was talking about translated gestures into sound, but this program translates gestures into visuals. It's like MS paint on a much grander 3D scale! I'm not sure if I would find it as easy to use however.