The mysterious Spinning Woman...

Been confounded for the last half an hour by this lady... who always spins (initially anyway) counter-clockwise for me (apparently this means I use the left side of my brain preferentially, which means I'm analytical). I suppose it follows that I've played with the image with my eyes until I can now change the direction she spins at will. Not sure whether this is strictly an IQ thing as suggested though - as there is a trick to it, which maybe bypasses the point. Still a vaguely interesting way to pass the time though, and intriguing if it's true... ^_^