I tried it too, it changes direction on its own. And you don't have to stare or concentrate, I Left it open and went to another page and when I came back it was going in the opposite direction. I was going to time it to see if it does it on a schedule but then thought to myself I must be crazy I have better things to do. maybe not..
about 35 seconds the first time (mississippi 1 etc.) about 30 the second