Programmer and Engineer

A Programmer and an Engineer were sitting next to each other on an air plane. The Programmer leans over to the Engineer and asks if he wants to play a fun game. The Engineer just wants to sleep so he politely declines, turns away and tries to sleep. The Programmer persists and explains that it`s a real easy game. He explains,`I ask a question and if you don`t know the answer you pay me $5. Then you ask a question and if I don`t know the answer I`ll pay you $5.' Again the Engineer politely declines and tries to sleep. The Programmer, now somewhat agitated, says, 'O.K., if you don't know the answer you pay me $5 and if I don`t know the answer I pay you $50! ` Now, that got the Engineer's attention, so he agrees to the game. The Programmer asks the first question, 'What's the distance from the earth to the moon?` Then Engineer doesn't say a word and just hands the Programmer $5. Now, its the Engineer`s turn. He asks the Programmer,`What goes up a hill with three legs and comes down on four?` The Programmer looks at him with a puzzled look, takes out his laptop computer, looks through all his references and after about an hour wakes the Engineer and hands the Engineer $50. The Engineer politely takes the $50 turns away and tries to return to sleep. The Programmer, a little miffed, asks, `Well what`s the answer to the question?` Without a word, the Engineer reaches into his wallet, hands $5 to the Programmer, turns away and returns to sleep.