As I sat in the elementary art class, on assignment as a substitute at the school, I listened to the teacher’s lesson to the children on concentric circles. The exercise would begin with a dot being drawn. A small circle would be drawn around the dot, then a larger one around that, and then a larger one, and so on, and so on. Each circle shared the same center. In this particular exercise, several series of concentric circles would be drawn on a large sheet of paper, overlapping each other. The different color patterns made quite a cool effect.