Sangaku are Japanese drawings of geometric puzzles and/or theorems. Here, I've tried to start with a simple case (a square and a circle inscribed in a larger circle) and then worked to develop an adjustable version to add many more circles. I don't have any particular theorems or relationships that I've proved -- I'm after the visual appeal. If you like these, you might enjoy more (static ones) that can be found at cut-the-knot. Scroll to the bottom to get a whole bunch. Others can be found here.