Knuth said

“[T]he TEX research project that I embarked on was driven by two major goals. The first goal was quality: we wanted to produce documents that were not just nice, but actually the best.”


“I never intended to have a system that would be universal and used by everybody. I always wanted to write a system that would be used for just the finest books.”

“The current version number for TEX is 3.1, and for METAFONT it is 2.7. If corrections are necessary, the next versions of TEX will be 3.14, 3.141, then 3.14159, . . . , converging to the ratio of a circle’s circumference to its diameter; for METAFONT the sequence will be 2.71, 2.718, . . . , converging to the base of natural logarithms. I intend to be fully responsible for all changes to these systems for the rest of my life.”

Donald E. Knuth
Digital Typography (1999)