Sorry the image is a little suggestive, but I couldn’t find this done with any other image, and you HAVE to try this.
First of all, note which direction the girl is spinning when you first get to the page. If she’s spinning clockwise you’re right brained — or at least thinking with your right brain. Can you get her to spin the other way?
One trick is to scroll down until you only see her feet, then slowly scroll back up to see the whole image. But a much cooler thing to try is to switch your thinking to the other side of your brain.
If you see the girl spinning counter-clockwise, try to think of something creative or emotional. Keep staring at the image and think of a song you like and imagine what images come to your mind as the music plays. If she changes directions, congratulations, you’re using your right brain.
If she’s spinning clockwise, try doing some math. Don’t do the multiplication tables or anything you know by rote. Try just adding random numbers together in your head. If she changes directions, you’re using your left brain.
Apparently only 14% of people can do the direction change thing, but I swear it worked for me. I tried the staring-at-her-feet trick first, but then I tried changing thinking styles and she flipped right before my eyes. Its really trippy when it happens!