There is some interesting discussion on the LaTeX stack overflow page about the challenge of detecting and preventing rivers during the typesetting process:
Avoiding rivers becomes a rather non-trivial optimization problem. In Holkner's paper he found that it took ~1 minute just to typeset 1200 words. Some of his experiments took more than six hours to complete.
Futility Closet had a cheerful, wholesome podcast for many years until abruptly ending it without much explanation. Glad to see they're still busy. Anyone know what happened? I always wondered.
I was under the impression they simply wanted to take a break. I thought the break was to be more permanent... but perhaps they found they couldn't quit it.
They said in their penultimate podcast episode (2021-11-22) that the Futility Closet blog would continue but that the following episode would be their last.
https://tex.stackexchange.com/questions/4507/avoiding-rivers...
https://tex.stackexchange.com/questions/29049/how-to-define-...
And if you really want to get into it, there is a rather detailed paper by Alex Holkner: https://gwern.net/doc/design/typography/tex/2006-holkner.pdf
Avoiding rivers becomes a rather non-trivial optimization problem. In Holkner's paper he found that it took ~1 minute just to typeset 1200 words. Some of his experiments took more than six hours to complete.