The C9 shape below is made up of pieces that repeat around a circle. Go clockwise around the circle, coloring every other repeated piece in the same way. That is, color a piece, skip a piece, color the next piece the same way as the first, and keep going. Do you end up coloring every piece? Can you use this to prove a 2/9 turn is or isn’t a generator for C9?

Answer: Yes; yes