This is a piece by M.C. Escher. It's called "Reptiles" and is a lithograph made in 1943. A lithograph is the method of printing when the work is etched onto a coating of wax that has been applied to a plate of lithographic stone. Only the etched piece will take up the ink, and the area that isn't supposed to be printed is treated to repel the ink. Escher is well known for doing most if not all of his works in a print form. When I first saw this, I thought it was a drawing because of all the shading and details.