"A program would develop the way a city develops," says Stallman, recalling the software infrastructure of the AI Lab. "Parts would get replaced and rebuilt. New things would get added on. But you could always look at a certain part and say, `Hmm, by the style, I see this part was written back in the early 60s and this part was written in the mid-1970s.'"
-- From the book Free as in Freedom by Richard Stallman.