a friend of mine just sent me an animation of a dancer spinning. apparently, if you see her turning clockwise you are using your right brain, and if you see her turning counterclockwise you are using your left brain. at first i saw her turning clockwise (right brain). then by concentrating i managed to shift back and forth between the two directions. it made my head hurt a little bit.
it's a really odd sensation.
http://www.news.com.au/heraldsun/sto...81-661,00.html
(the animation she sent me is turning faster than this one. it seems easier to shift back and forth than the slower one. but it's still possible, if you concentrate.)