Groucho: Now here is a little peninsula, and over here is a viaduct leading over to the mainland.
Chico: Why a duck?
Groucho: (after a pause)I’m fine, how are you? I said this is a viaduct leading over to the mainland.
Chico: All right, why a duck?
Groucho: I say that’s a viaduct.
Chico: All right, why a duck? Why a duck? Why not a chicken?
Groucho: Well, I don’t know why not a chicken. I’m a stranger here myself. I know that’s a viaduct. You try to cross over there on a chicken and you’ll find out why a duck.
Chico: But why-
Groucho: It’s deep water, that’s why a duck. Look here, suppose you were out horseback riding and you came to that stream and you wanted to ford over. But you can’t. It’s too deep.
Chico: What would you want with a Ford when you got a horse?
Groucho: (after a pause)Well, I’m sorry the matter came up. I just know that that’s a viaduct.
Chico: Listen. I catch on to why a horse, why a chicken, why a this, why a that, but I don’t catch on to why a duck.
Groucho: I was only fooling. I was only fooling. They’re going to build a tunnel there in the morning. Is that clear to you?
Chico: Yes, everything except for why a duck.