Art school!
Glad to see someone who's studied thier books. Contrast is important as one of the elements of art. (Line, Color, Shape, Contrast, Emphasis, Repetition, etc.) I'm extremely pleased to see that you've thought about these elements as you've implemented them. I think everyone on NG should take at least one course in Art Theory or Histotry.
Pat yourself on the back, you've made an excellent animation! Keep up the good work.