Friday Illusion: Escher's gravity-defying waterfall

[n2doc]

Catherine de Lange, reporter
You've probably seen the Dutch artist M. C. Escher's work, even if you don't know him by name. Escher is famous for mathematically-inspired pictures of structures that look perfectly normal at first glance, but turn out to be impossible on closer inspection.
One of his most famous works is Waterfall, in which a stream of water pours from the top of a watermill into a pool at its base - and then bafflingly flows "uphill" to pour from the top all over again. The visual effect is certainly clever, but impossible to recreate in the real world - or is it?

In the video (at link), when water is poured into the bottom of the contraption it appears to flow upwards, seemingly in defiance of gravity. Of course, there must be some sort of trick involved: we've shown you before how careful camera-work and clever 3D structures can play games with your brain.
But so far, the ingenious builder of this illusion - known as mcwolles on YouTube - has yet to reveal how he created it. Can you figure it out? Let us know in the comments! And we'll ask the experts for their opinions too.

video:

http://www.newscientist.com/blogs/nstv/2011/02/friday-illusion-eschers-gravity-defying-waterfall-brought-to-life.html

[tridim]

1. Looks like a composite image to me.. The aparatus is a 3D CGI model.

He's pouring the liquid into the only real part, which is built to hide the poured water.

[Posteritatis]

6. Nah, it's just forced perspective. (nt)

[Sonoman]

2. OK, that's about as cool as it gets.

Thanks and KnR.

Sonoman

[MineralMan]

3. Can't quite visualize the trick there.

Clearly, the whole thing's on the floor, and you can see that the bases for each platform diminish in thickness as the tower goes "up." But...I can't quite visualize how the illusion is created. I'm thinking this has a very narrow angle of view for the illusion, and any camera movement to either side would reveal the actual construction.

I disagree about its bein CGI.

[pokerfan]

4. Forced perspective I think

and a hidden pump somewhere. I was hoping that he'd move the camera at the end, breaking the forced illusion and show us how it works ala Penn & Teller. You can entertain and educate at the same time.

Like this one: http://www.youtube.com/watch?v=U9PZizBDBZw

[MineralMan]

5. Well, it's clear that all the levels are on the floor, given the pour in the

video. The height thing is an illusion, as you say, using forced perspective from that particular viewpoint. The key, for me, was the shallower depth of each level of the trays. There's a continuous slope from the pouring point to the top.

The illusion of height is done with the components that look like supports for the various levels, and by the nonfunctional top shelves. Exactly how the maker did that, I can't tell, but another view would make it clear.

[Kaleva]

7. Doesn't the shadow of the contraption look odd?

Also, when the guy is pouring the water into the device, his shadow by the broom becomes quite jerky.