Tony: (laughing)I think this is really funny!

Betty: Why? I don’t get the joke.

Tony: Look! In the first picture, there’s a man running away from a policeman.

Betty: But why is he running away? I don’t understand.

Tony: Well, he’s done something wrong! The policeman wants to catch him.

Betty: I see. And then the man runs into the lift.

Tony: Yes, and this is the funny bit. It’s really clever! The policeman could catch the man in the lift, but he doesn’t. They both just stand there, waiting for the lift to stop!

Betty: Now I get it! Yes, it is funny!

Tony: Yes, and as we see in the last picture, the policeman is still trying to catch the man!