Rotating Girl Illusion

My friend Bill sent me this amazing image:

Look at the image and see which way the girl is rotating - clockwise or counter-clockwise. This is the amazing part, which you may find difficult to believe at first - you can actually get the girl to spin either way based on how you view and interpret the image.

When I first looked at the image, she was spinning clockwise. This supposedly means I am very "right-brained", which of course is true. Once she started spinning counter-clockwise, I found it very difficult to get her to start spinning clockwise again.

Now I am actually able to get her to spin either way at will. Try it - this is not a trick.