How do you get the ballerina to spin the other way?

http://www.heraldsun.com.au/news/right-brain-v-left-brain/story-e6frf7jo-1111114603615

No matter how long I stare at it I just can’t seem to swap it.

Also I believe that test to be complete bull, but I just want to be able to switch the ballerina spinning to the other way :D.

So what strategies, if you can describe, do you use if you can make her spin either way at will.