Optical Illusion?

[Samurai Waki]

I can see it going just CW

[Warmaster Horus]

Erm, that's definitely clockwise for me; but my parents said they could see it counter-clockwise briefly.

[Samurai Waki]

Aha! I got it. You have to very closely Concentrate on the foot. And I mean close... like my eyes were practically touching my computer screen, and as soon as I noticed the change backed my head away, and now it won't change back to CW!

[shlin28]

Hehe... now I can change the direction at will.

Blinking helps

[GeneralHankerchief]

Hehe... now I can change the direction at will.

Blinking helps

Try doing it while you're staring at the head.

[Husar]

Mostly clockwise, with some concentration counter clockwise but it everytime she is at 3 or 9 o'clock my brain tries to make her change direction.

[Csargo]

The picture switches back and forth. From Counter-clockwise to Clockwise. it's the pic.

[Sasaki Kojiro]

Yeah, it's an illusion. It's easiest to get it to switch by looking at the feet. Cover up the rest of the body, then look and see which leg is passing "in front of" the other one. Then convince yourself that it's actually passing behind it.

[Csargo]

NOW SHE'S DOING CARTWHEELS AMAZING!!!!

[Whacker]

I absolutely cannot see the clockwise rotation. I guess that's fine though, because I am definitely am left-brain dominant.

Edit - I just realized I posted wrong. Fixed.

[Charge]

I absolutely cannot see the counter-clockwise rotation.

Same...

[Husar]

I played around a bit in Corel Draw and erm maybe this helps in some way, I found the fast rotation a bit too fast...



The question is what can we gather from the shadow?
It's closer to her foot when it moves from the right to the left, to me that means the foot is further away and when it moves closer, the shadow is outside the picture, thus she would rotate counter clockwise.