One of M.C. Escher's most popular lithographs, created in 1960. Escher was best known for depicting three-dimensional impossibilities in two-dimensional works of art, and this is one of the more intriguing -- a staircase around the top of a simple tower which goes down, down, down, down (or up, up, up, up, depending on your perspective) -- and continues to do so, all the way around the tower. Two lines of hooded figures occupy the steps, one ascending them and the other descending, neither one looking at the other. The idea for the staircase illusion itself originated with the father of Roger Penrose, not with Escher, and is the basis for his "Waterfall" print as well.

Escher himself drew a parallel between this novelty and the world around us -- and it's this understanding of the work that makes it my favorite of all of his. He said (in Dutch, of course):

That staircase is a rather sad, pessimistic subject, as well as being very profound and absurd.... Yes, yes, we climb up and up, we imagine we are ascending; every step is about ten inches high, terribly tiring -- and where does it all get us? Nowhere; we don't get a step farther or higher. And descending, running down with abandon, is not possible either.

People don't like to talk about falling; they'd much rather talk about ascending. Well, then... I'm working my fingers to the bone, believing I'm ascending. how absurd it all is. Sometimes it makes me feel quite sick.