Watch when the lady's foot "kicks" the letter. The letter flashes for a split-second, right-to-left on the clockwise version, left-to-right on the other. It's barely perceptible, but that's all you need for your brain to think the lady's foot is moving in the same direction that the letter is flashing.
Without that visual guide, your brain reverts to thinking the lady is spinning the way it wants her to.