The spinning girl image can let you know which part of your brain works for you and how you perceive thing normally.
Which way is she spinning for you?
Clockwise or Anti Clockwise
If clockwise you are using your right side of you brain. If anti clockwise you are using your left side of your brain. It is not that difficult to experience the anti clockwise or vice versa, all it takes is to move your eyes away from the image for few seconds and view the spinning girl again.