Oh, a beautiful Renaissance landscape by one of those Lowland masters, a naturalistic scene of people meeting merrily on a wooded path between the village center and some large, important houses. In the background, rolling hills and farmers’ fields gradually fade into the misty distance. Lovely. But what’s this thing in the middle with the birds around it? There’s one bird on its crosspiece, and then another off to the right by the thing’s front leg. No wait, back leg. No… wait…. Who put that together? And HOW?
Bruegel is playing here with a very ordinary-looking scene based around an impossible object, a thing that uses the rules of perspective to trick our sense of space. There’s a whole family of related optical illusions including the delightful Penrose triangle. You just don’t find them in landscapes all that often.