[commodoredl]

I think the issue Bob is worried about is that, since your flapper is spinning, at some point it will be fully vertical and contained within the Frame Perimeter. When that happens, the last part of Rule G30 takes effect, disallowing any of that flapper from exiting the Frame Perimeter for another two seconds. Which will happen, since the flapper would continue spinning after it reached a vertical position.
Does your spinning device at any point in its spinning reach a position in which the flaps are fully contained inside the frame? If so, you have a problem.