The Penrose rectangle is what's known as an impossible object. It's an optical illusion, drawn to look like a three-dimensional object -- but one that could never actually exist. Op artists like Victor Vasarely exploited this visual dynamic, adding color and creating a new art form.Ers9949 finish: solid brass, electro-plated with hematite finish, giclee print, ear wires are plated hematite dimensions: hangs approx. 1.75" (gift boxed with provenance card).