I agree.
When rotating clockwise (as seen from above) she is bouncing on her left leg. She switches to the other leg when she changes rotation. The transition periods seem to come at random, and are separated by a short interval where she rocks back and forth from one leg to another.
I'm not really sure I'm just not being fooled (that, after all, is the whole point of an optical illusion) but that is what I think I see. I suspect the shadows have been added just to distract us.
