"Surely You're Joking, Mr. Feynman!" - unam.

I asked the Bell Labs if they would let me work for the army that summer, and
they said they had war work, too, if that was what I wanted. But I was caught up in a
patriotic fever and lost a good opportunity. It would have been much smarter to work in
the Bell Labs. But one gets a little silly during those times.
I went to the Frankfort Arsenal, in Philadelphia, and worked on a dinosaur: a
mechanical computer for directing artillery. When airplanes flew by, the gunners would
watch them in a telescope, and this mechanical computer, with gears and cams and so
forth, would try to predict where the plane was going to be. It was a most beautifully
designed and built machine, and one of the important ideas in it was non­circular gears ­­
gears that weren't circular, but would mesh anyway. Because of the changing radii of the
gears, one shaft would turn as a function of the other. However, this machine was at the
end of the line. Very soon afterwards, electronic computers came in.
After saying all this stuff about how physicists were so important to the army, the
first thing they had me doing was checking gear drawings to see if the numbers were
right. This went on for quite a while. Then, gradually, the guy in charge of the department
began to see I was useful for other things, and as the summer went on, he would spend
more time discussing things with me.
One mechanical engineer at Frankfort was always trying to design things and
could never get everything right. One time he designed a box full of gears, one of which
was a big, eight­inch­diameter gear wheel that had six spokes. The fella says excitedly,
"Well, boss, how is it? How is it?"
"Just fine!" the boss replies. "All you have to do is specify a shaft passer on each
of the spokes, so the gear wheel can turn!" The guy had designed a shaft that went right
between the spokes!
The boss went on to tell us that there was such a thing as a shaft passer (I thought
he must have been joking). It was invented by the Germans during the war to keep the
British minesweepers from catching the cables that held the German mines floating under
water at a certain depth. With these shaft passers, the German cables could allow the
British cables to pass through as if they were going through a revolving door. So it was
possible to put shaft passers on all the spokes, but the boss didn't mean that the
machinists should go to all that trouble; the guy should instead just redesign it and put the
shaft somewhere else.
Every once in a while the army sent down a lieutenant to check on how things
were going. Our boss told us that since we were a civilian section, the lieutenant was
higher in rank than any of us. "Don't tell the lieutenant anything," he said. "Once he
begins to think he knows what we're doing, he'll be giving us all kinds of orders and
screwing everything up."
By that time I was designing some things, but when the lieutenant came by, I
pretended I didn't know what I was doing, that I was only following orders.
"What are you doing here, Mr. Feynman?"
"Well, I draw a sequence of lines at successive angles, and then I'm supposed to
measure out from the center different distances according to this table, and lay it out. . ."
"Well, what is it?"
"I think it's a cam." I had actually designed the thing, but I acted as if somebody
had just told me exactly what to do.
The lieutenant couldn't get any information from anybody, and we went happily