UML Surrealism

Remember the classic UML “sailboat” book Applying UML and Patterns?
It has kind of a neat image on the cover of a picture of a sailboat, a uml diagram of a sailboat, along with the words “This is not a sailboat”.
(Click on the image to zoom in):
Amazon link
Never noticed before, but I bet it is a tip of the hat to this:
Wikipedia link