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, eight-inch- diameter 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.