TeX
Software / App
A typesetting system created by Knuth. He wrote almost the entire manual for TeX during machine downtime at the Stanford AI Lab. Knuth released TeX as open source to prevent proprietary rights from hindering progress in typography.
Mentioned in 2 videos
Videos Mentioning TeX

Donald Knuth: Programming, Algorithms, Hard Problems & the Game of Life | Lex Fridman Podcast #219
Lex Fridman
A typesetting system created by Knuth. He wrote almost the entire manual for TeX during machine downtime at the Stanford AI Lab. Knuth released TeX as open source to prevent proprietary rights from hindering progress in typography.

Donald Knuth: Algorithms, Complexity, and The Art of Computer Programming | Lex Fridman Podcast #62
Lex Fridman
A typesetting system created by Knuth, along with Metafont and Computer Modern typefaces, which defined the aesthetic for scientific and mathematical papers.