If you see this girl turning in a clockwise rotation, you are using the right hemisphere of your brain.
If you see her turning counter-clockwise, you are using your left brain hemisphere.
Some people see both ways, but most people see her spinning only one way.
If you try and do see her spinning in the opposite direction, your IQ is above 160 which is genius.
Then see if you can make her spin one way and then the other.
Steven Novella, in "Neuroscience Comments", explains that you can see the girl spinning both ways by switching the brain's current.
BOTH DIRECTIONS CAN BE SEEN.