A man and his wife have been stranded on a deserted island for many years. One
day another man washes up on shore. He and the wife are very attracted to each
other right away, but realize certain protocols must be observed. The husband,
however, is very glad to see the second man there. "Now we will be able to have
three people doing eight hour shifts in the watchtower, rather than two people
doing 12-hour shifts."

The new man is only too happy to help and in fact volunteers to do the first
shift. He climbs up the tower and is soon standing watch. Soon the husband and
wife start placing stones in a circle to make a fire to cook supper. The second
man yells down, "Hey, no fucking!" They yell back, "We're not fucking!"

A few minutes later they start to put driftwood into the stone circle. Again
the second man yells down, "Hey, no fucking!" Again they yell back, "We're not
fucking!"

Later they are putting palm leaves on the roof of their shack to patch leaks.
Once again the second man yells down, "Hey, I said no fucking!" They yell back,
"We're not fucking!"

Finally the shift is over so the second man climbs down from the tower and the
husband starts to climb up. He's not even halfway up before the wife and second
man are screwing each other's brains out. The husband looks out from the tower
and says, "Son-of-a-gun... From up here it DOES look like they're fucking!"