A Day in the Life of an M.C. Escher Drawing

In this comedic piece, Eschers famous print Ascending and Descending is featured. Two of the men walking the never-ending staircase carry on a conversation.

One of the men offers the other a banana. As to be expected, one slips on the banana and continues falling down the stairs. How does M.C. Escher create an illusion of depth? What does this piece symbolize?