Dowager Countess: Good heavens, what am I sitting on?
Matthew: A swivel chair.
Dowager Countess: Another modern brainwave?
Matthew: Not very modern, they were invented by Thomas Jefferson.
Dowager Countess: Why does every day involve a fight with an American?
Matthew: I’ll fetch a different one.
Dowager Countess: No, no, no, no – I’m a good sailor.
Uncle Bub: Did you know that I invented the peanut butter and jelly sandwich?
Timothy Green: Did you know that I’m a big fan of your work?
Probably the last man who knew how it worked had been tortured to death years before. Or as soon as it was installed. Killing the creator was a traditional method of patent protection.