I'm not a trusting soul... I saw her spinning one way, then the other ... and it would flip back and forth. Drove me nuts. So, being a computer person and someone who has dabbled in graphics, I decided to download the file and split it up to see if it was a trick.
I am here to say ... she goes in the graphic file frame by frame one way ... so when you see her flip ... the sides of your mind is doing that ... it's a bit of an optical illusion for me :)