Joseph Bloggs: "I can't follow it, my dear boy. It makes me dizzy!"

John Snoggs: "It's very simple. Listen again! You happen to be my

father's brother-in-law, my brother's father-in-law, and also my

father-in-law's brother. You see, my father was--"

But Mr. Bloggs refused to hear any more. Can the reader show how this

extraordinary triple relationship might have come about?

Amusements in Mathematics · 第 72 / 970 题