Real or Fake? Impossible Wooden Waterfall

It takes a special kind of mind to look at an M.C. Escher drawing and see a blueprint. And yet, looking at this working 3D model of Escher's Waterfall, one gets the impression that YouTube's mcwolles may have done just that!

One thing's clear: like Escher's famous lithograph, the video employs some manner of trickery. But what kind? Good, old-fashioned forced perspective? CGI? Do the shadows provide a clue? Let's hear it in the comments. 

UPDATE! One viewer thinks he may have the answer:

Want more Escher-inspired madness? Be certain to check out these mind-bending LEGO replicas!