The Penrose stairs are neverending; they look as if they go up or down, around corners, and all in the same direction, and yet they are joined together so that anyone walking them will go round and round and round… They rise, or fall, forever and yet they meet at every corner. At least, that’s what it looks like.
Escher was introduced to the idea of those strange stairs through Roger Penrose, a geneticist who designed a physical model of them. (The concept had been independently discovered and refined years before by the Swedish artist Oscar Reutersvard, but Roger Penrose knew nothing about his work.)
The idea is so intriguing that many have been drawn to it since. Enrique on YouTube, explains the Penrose Stairs as a real object, and shows how depth and perspective are used to create the illusion.
Others have created musical versions of the illusion, like the one on this page.
Escher took the idea and played with it. In his picture “Ascending and Descending” figures walk around and around the top of a building, some going up and some going down – or at least so it seems. They ascend and descend and yet never leave the level they are on.
Of course, he makes the whole thing look possible. We want to believe what we’re seeing. But it’s an illusion.