Counting Stacks
I saw today some clever mathart by Mel Bochner. In a gallery description, it says "In the wake of abstract expressionism artists felt there was little to add to painting and this triggered in Bochner a response that was more about thinking than making. He started to find clear ways of looking at art and to question how we experience depth, perspective and space. He went on to explore language and colour in the same way."
See his work at the Simon Lee Gallery site.
I like these for their random compositions, but I think you might be able to use them like teachers use dot diagrams. How many do you see? How do you know?