Escher - "Relativity"

This is "Relativity" a 1953 lithography by Escher and one of his most famous works.
It is amazing that his work is so well known and inspired not only artists but also propaganda, graphic designs and other areas, even mathematics.
We are not in a somewhat imaginary world like at the Piranesi stairs three posts below.
It is gravity the main issue here. It also deals with perspective and the explicitness representation of three-dimensional space in the two-dimensional medias one of the recurrent themes of Escher's work.
The right image is from the site Escher for Real that I have already showed at this other post about Escher.
If you want to know more about Escher The Official M. C. Escher Website has many informations.

" I am always wandering around in enigmas. There are young people who constantly come to tell me: you, too, are making Op Art. I haven't the slightest idea what that is, Op Art. I've been doing this work for thirty years now."

" The things I want to express are so beautiful and pure."

" So let us then try to climb the mountain, not by stepping on what is below us, but to pull us up at what is above us, for my part at the stars; amen."

" I play a tiresome game."

" I don't grow up. In me is the small child of my early days."

M. C. Escher

I remember the first time I saw Escher works. It is always an amazing experience. I wanted to put other pictures but it would be too much.

Update:
Lots of stairs! Escher, Piranesi and Duchamp.
In a way I think of them as counter-parents.