(From all my faves but this is not the first place I've seen it.)
Look at the dancer below. What do you see? Is she turning clockwise or counter-clockwise? You just can’t help but love these optical illusions.
If you see her turning clockwise (right) then your left side of the brain is doing most of the work, which means you are more of a logic/analyzing person.
If you see the dancer turning counter-clockwise (left) then your right side of the brain is in charge, this means you are the artistic/intuition person.
The first time I saw her somewhere in the world wide web I saw her spinning anti-clockwise. I got my sister over and she saw her spinning clockwise, but after staring for a short while, my sister claims that the ballerina now spins anti-clockwise. But I could still only see her spinning anti-clockwise.
After I came to this webbie again, I still can only see the damned ballerina spinning anti-clockwise. I passed the link over to Someone who proceeds to claim ther he could only see her spinning clockwise. Then I got my sister over just now to examine the gif image again, and she claims that the ballerina sometimes was spinning clockwise then stops and changes direction and spins clockwise, and then stops and changes again, and this went on. Still only being able to see the ballerina spinning anti-clockwise, I protested to my sister that I can't see what she was seeing.
Then my sister went to get a stuffed toy and proceeds to display to me in real life action what she saw, she went and turned the toy first to the left then to the right and to the left and to the right. And I saw none of that happening in that image.
Grr... So in short, I guess me is the artistic/intuitive one while Someone is the logical/analysing person, and my sister is the more balanced person.
What do you see?