Everyone has seen M. C. Escher’s famous lithograph Ascending and Descending of the perpetually ascending and descending staircase. Of course, we all know that this is an optical illusion and that such a thing could not be made in real life.
Or could it?
Take a look at this.
Of course, this has to be a trick and Snopes says that it was the project of a graduate student at the Rochester Institute of Technology aimed at creating an internet myth. It is done with mirrors and tricky camera angles and editing.
I don’t know exactly how it was done but you can see it involves some trickery by looking closely at the boy’s left arm in the following video.
Still, it is pretty ingenious.