I saw a link on reddit the other day regarding some math-related videos, including a series of lectures by Don Knuth , including some on TeX internals. (One frustrating bit about the Web video is the blurriness of his terminal. Another is that he uses what is now a slightly-out-of-date version of TeX itself). He made a comment near the beginning of section 3, probably similar to things he has written, to the effect that in his education he had benefited both from reading badly-written programs, because they were evidence he could do better, and from well-written programs, because they were a pleasure to read. He then wondered aloud which category TeX is in, but that either way it was a win. I'm not at all sure myself. Perhaps TeX is a monument to the best that can be done in Pascal, and simultaneously a warning that it is the best that can be done in Pascal. I had a definite feeling during grad school, when I was learning LaTeX to write my thesis, and learning Lisp on the side,...