Shapes:

Equal inner and outer, small Divisions, will yield geometric shapes.  160, 160, 8 is an octagon.  160, 160, 4 is a square.  But 160, 226, 8 is also a square.  160, 160, 100 is a circle.  

With points left at 100, reduce both radii equal amounts before each draw and a series of evenly reduced circles will be drawn.

With experimentation, similar series can be drawn in any shape.

Another series I’ve done is to reduce the radii an equal amount with each draw and the Divisions one notch, as well.

With 500 x 500 x 100 combinations, there’s 25,000,000 different draws possible.  Multiply that by 356 colors and that’s 6,400,000,000.

Have fun!