OLD MAN: What is it that’s green, hangs on the wall, and whistles?
YOUNG MAN: I don’t know. What is it?
OLD MAN: A red herring.
YOUNG MAN: But it isn’t green.
OLD MAN: So you can paint it green.
YOUNG MAN: But it doesn’t hang on the wall.
OLD MAN: There’s a law saying you can’t hang it on the wall?
YOUNG MAN: But it doesn’t whistle.
OLD MAN: No, it doesn’t whistle... I just threw that in to make it hard to solve