it's an MC Escher waterfall. I mean clearly that's impossible, so it's an illusion of some sort. The very shape of the thing can't be built, but it looks very good. I'm guessing the angle from which you view it is pretty critical.

Yes the angle is of importance, I do not know how he did the water bit.

The last L section are separate to the rest of the water fall, you can kind of notice when the water goes round and the shadows fall slightly differently, and there will be a pump to get the water on to the last section... Angle is very important...

yes, well spotted, it's that last section !

also.... he only tips 1 jug of water in.... but it looks like there's more than a jug full going round to me

it's very well done tho!  must have taken a lot of time to setup!

This is probably how it is done:

http://www.boingboing.net/2011/02/18/is-this-how-the-esch.html