Interesting article with a challenge at the end. Alas, no mention of the earlier and less versatile eqn/troff (along with tbl and pic) to contrast with Knuth's

Interesting article with a challenge at the end. Alas, no mention of the earlier and less versatile eqn/troff (along with tbl and pic) to contrast with Knuth's end-to-end system. https://en.wikipedia.org/wiki/Eqn https://en.wikipedia.org/wiki/Eqn