Mr N

this is not an illusion! she blatantly changes direction anyone can see that!

Weird isn't it!

This is an optic illusion caused by the ambiguity of relative depth relationship between the two legs when they overlap and cross each other in the process ofrotation. That is, at the point of crossing, the leg in vertical orientation can be seen either as in front of the rotating leg or as in back of the rotating leg, and vice versa. In fact, if you cover the upper part of the toros so that only the two legs are in view, you can experience an even stronger illusion in that the dpeth relationship between the two legs can also be changed almost at will. This illusion essentally is of the same principle as the illusion one would experience when we see a 3D version of the well-known Necker cube set into rotation.

I can only see her moving clockwise. Which means what? I'm more creative than most people?

This is not an illusion at all. I scrolled down so i could only see the foot she is spinning on, and saw how the program changed to make her change directions. It has nothing to do with illusion, and everything to do with trickery. do not be fooled.

That's an interesting comment. So what you are saying is that the illusion still works on just her foot!

Different people see her spinning in different directions at different times. People also disagree on when she changes directions, and some never see her switch.

How can that not be an illusion. Perhaps you can share your insight on the foot?

actually... it is an illusion. on the pause menu of the video game 'Assassin's Creed' there's a spinning memory strand. if you stare at it long enough it changes directions... just like the girl.
IT'S IN YOUR MIND!
Oh, and if you still think it's an illusion... try looking at it with a friend to see if you both see the change in direction at the same time.

why does it become harder to visualize the picture changing direction when it is spinning slower?

The reasons why the dancing lady changes direction is explained here by Beau Lotto in his TED talk: Optical illusions show how we see.