The Engineer and the Progammer

A programmer and an engineer are sitting next to each other on a long flight  from LA to NY.  The
Programmer leans over to the Engineer and asks if he would like to play a fun game. The Engineer just
wants to take a nap, so he politely  declines and rolls over to the window to catch a few winks.
The Programmer persists and explains that the game is really easy and a lot of  fun.  He explains 'I ask
you a question, and if you don't know the answer, you  pay me $5.'  Again, the Engineer politely declines
and tries to get some sleep.
The Programmer, now somewhat agitated, says 'OK,  If you don't know the answer  you pay me $5, and
if I don't know the answer, I will pay you 50!' This catches the Engineer's complete attention, and he
sees no end to this torment unless he plays, so he agrees to the game.
 The Programmer asks the first question.  'What's the distance from the earth to  the moon?'  The
Engineer doesn't say a word, reaches in to his wallet, pulls  out a five-dollar bill and hands it to the
Programmer.  Now, it's the  Engineer's turn.  He asks the Programmer:  'What goes up a hill with
three  legs, and comes down with four?'
The Programmer looks at him with a puzzled look.  He takes out  his laptop computer and searches all
his references.  He taps into the Airphone with his modem and searches the Net and the Library of
Congress.Frustrated, he
 sends E-mails to all his co-workers and friends he knows. All to no avail.
 After over an hour, he wakes the Engineer and hands him $50.  The Engineer politely takes the $50 and
turns away to get back to sleep.  The Programmer,  more than a little miffed, shakes the Engineer and
asks, 'Well, so what IS the answer?'
 Without a word, the Engineer reaches into his wallet, hands the Programmer 
$5 and goes back to sleep.