The Lawyer and the Fisherman

A lawyer and a fisherman were sitting next to each other on a flight. The lawyer was bored and decided to play a game.
He said, “Let’s play a game. 
I’ll ask you a question, and if you can’t answer, you pay me $5. Then you ask me a question, and if I can’t answer, I’ll pay you $500.”
The fisherman, not one to pass up an easy $500, agreed.
The lawyer asked, “What’s the distance between the Earth and the moon?”
The fisherman didn’t know and handed over $5.
Then it was the fisherman’s turn. He asked, “What goes up a hill with three legs and comes down with four?”
The lawyer, stumped, pulled out his laptop, searched the web, and after a long time gave up. He handed the fisherman $500.
The lawyer then asked, “So what’s the answer?”
The fisherman handed him $5 and went back to sleep.