While i seriously doubt gray matter hemisphere dominance can be tested this easily, since in this case much depends on what part of the pic you focus first and in what stage you take a look at it, i still found this gif animation quite cool. It's not a loop because everyone will have a different reaction to it.
www.news.com.au/dailytelegrap...012895,00.html (external - login to view)
If you can't get it to change for you, scroll down for a bit till you cant see the picture, then wait a few seconds, then scroll up again but only till see the shadow. Imagine the figure going counter-clockwise. Scroll up.