Bits and Pieces, December, 1989, pp. 20-21
Years ago new engineers in the Lamp Division of General Electric were assigned, as a joke, the impossible task of frosting bulbs on the inside. Eventually, however, an undaunted newcomer named Marvin Pipkin not only found a way to frost bulbs on the inside but developed an etching acid that gave minutely rounded pits instead of sharp depressions. This materially strengthened each bulb. Fortunately, no one had told him it couldn't be done, so he did it.