I'm with gr8tshades - I think it randomly switches and they're just having a laugh at our expense. laugh

There's just no way you can "make" something go 'right to left' or 'left to right' in a moving image that isn't already programmed to be there. If it was a stationary image, sure. But it's not.

Lois: You know, I have a funny feeling that you didn't tell me your biggest secret.

Clark: Well, just to put your little mind at ease, Lois, you're right.
Ides of Metropolis