"The Programmer and the Engineer" joke

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 real easy and a lotta fun.
He explains "I ask you a question, and if you don't know the
answer, you pay me $5. Then you ask me a question, and if I don't
know the answer, I'll pay you $5." Again, the Engineer politely
declines and tries to get to 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'll pay
you $50!" This catches the Engineer's 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, but
reaches into 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 on four?" The
Programmer looks up at him with a puzzled look. He takes out his
laptop computer and searches all of his references. He taps into
the Airphone with his modem and searches the net and the Library
of Congress. Frustrated, he sends e-mail to his co-workers - all to
no avail.
After about an hour, he wakes the Engineer and hands him $50.
The Engineer politely takes the $50 and turns away to try to get back
to sleep. The Programmer, more than a little miffed, shakes the
Engineer and asks "Well, so what's the answer?" Without a word,
the Engineer reaches into his wallet, hands the Programmer $5,
and turns away to get back to sleep.