A cop walking his usual beat sees an old man pulling a box on a leash, down a busy street. „Poor man,” the cop thinks to himself. „I’d better go humor him.”

„That’ a nice dog you got there,” says the cop to the old man.

„It isn’t a dog, it’s a box,” replies the old man.

„Oh, I’m sorry,” says the policeman, „I thought you were simple-minded.”

The old man walks past the cop, then turns to his box, and says, „We sure fooled him that time, didn’t we, Rover?”