May 17, 2012 
A must-see video of an incredible optical illusion …
All you need to do is focus on the cross, which is located in the middle of the video. It will be quite enough for turning the irresistible Cameron Diaz into an ugly version of her …
Pogledajte video
The illusion was accidentally discovered by a student at the University of Queensland Sean Murphy. He studied the phenomena with the help of his colleagues Jason Tangen and Matthew Thompson.
Effect is interpreted as follows:
In the situation when the image of two faces are aligned in a way that eyes are on the same line, and you quickly switch images, our brain begins to experience each face through the prism of one next to it.
This leads to highlighting their differences, so otherwise pretty faces suddenly seem grotesque.
Taken from: www.24sata.hr