Box Flip Effect

Anybody want to take a guess on how these guys did this effect?
It’s the box flip effect that occurs when you flip over one of the toy boxes.
www.crew11.net

Could it be a PNG sequence? I personally think it’s done by scaling and X blurring. But I don’t know how they got it to look so good. And it doesn’t seem like a PNG sequence because the flash file is only 4.2MB and there are a ton of boxes to choose from.