optical illusion: the dancer spinning ... and its explanation 
spectacular optical illusion is known as Spinning Silhouette Optical Illusion
(optical illusion of rotating figure) and was created by Nobuyuku Kayahara in 2003.
It can be seen with a girl turning to the left "? "Right? Therein lies the surprise: it turns both ways and depends on the observer to rotate to either side. Moreover, with a little practice you can get that rotate in the sense that we want and whenever we want. You just have to take the time to "order" that change the direction of rotation ...
This image actually sent me an email. This is not a gif to be changing direction, the proof is that you look at the dancer among many: each will turn to the side and changing direction at different times. In the email, which you can see how was here, provides an explanation is sufficient for cumbersome, relegating it to a kind of magic assertion. It's laughable to read that "if you can see the figure turning in both directions, it means that your IQ is above 160, almost a genius." Irrefutable proof, course. As I said two posts ago, the boundaries between science and pseudoscience are often very clear.
The explanation I found is right at the source that I linked in this post. Just found this explanation looking the illusion of the horse to illustrate the mine. Because it is made not repeat, but the bonds. Get here if you have not heard where he was.
Finally, I keep thinking it was a girl in a comment to this post where you called genius to see her spin in both directions ( here ): "I have 14 years and feels good in school ... like I can be a genius? d turn I see the 2 ways. "
