|Maybe not the safest thing to do, but pretty fun, anyway.|
They dumped a whole bunch of little plastic balls on an escalator to see what would happen.
The result is pretty fascinating: The balls try to roll down the stairs, but the escalator is going up, so many of the balls stay on the escalator, bouncing up and down as the escalator moves.
It's sort of a perpetual motion machine.
The video was released more than two years ago but has lately gone viral. It popped up on the Web site BoingBoing recently, via JWZ
Here's' the fun video: