MC Escher's Waterfall

My dad has pointed me to a video on youtube that shows MC Escher's waterfall but actually real and working, which is a pretty impressive feat seen as it is an impossible object. the video is bellow;

 



If you were to view the illusion from a different angle you would be able to see how it is set up although we are not able to get a different view, it is possible to gain clues fom shadows and lighting to understand how it works. this shap eyed youtuber explains below;

 

Many thanks to John Boffin fo sending me the link.