How does the impossible waterfall model

known that the laws of physics, water can not flow upwards, but the famous Escher lithograph spodvigla this guy on the creation of such a spatial illusion. And he wants to convince us that everything the way it is - the water flows up! Of course, this is nothing more than a trick, and that's one of the versions, reveals the secrets of this waterfall:
is not so important - pump, or just create a video montage a full sense of the paradoxical movement of the water, it is important that this trick with water again not everyone can.