It might amuse you, or maybe you don't care, but when I was a grad student I gave my Pascal students the traveling saleman problem. I told them how hard it was (NP-hard) and said if you can find a solution that works in polynomial time, I'll dedicate my life to you to get you a Nobel Prize. I was too green to know about Turing awards. I had a math guy in the class who called me up, land lines, at 3am on a Sunday morning (Saturday night so he was working on this instead of going out to have fun). Screamed at me that he had it. He didn't. Still fun to get the kids thinking. Seems like Kernighan and Lin thought harder. On Sun, Sep 29, 2024 at 11:30:42AM +1000, Rob Pike wrote: -- --- Larry McVoy Retired to fishing http://www.mcvoy.com/lm/boat

At 2024-09-28T19:20:07-0700, Larry McVoy wrote: troff didn't exist yet in 1971. That is proper typesetting, though. I don't know enough to say if it's phototypeset or hot lead (can the naked eye reliably tell, if both techniques are of high quality?). We could take the question to the real typographers on the groff list. roff(7): Third Edition Unix also brought the pipe(2) system call, the explosive growth of a componentized system based around it, and a “filter model” that remains perceptible today. Equally importantly, the Bell Labs site in Murray Hill acquired a Graphic Systems C/A/T phototypesetter, and with it came the necessity of expanding the capabilities of a roff system to cope with a variety of proportionally spaced typefaces at multiple sizes. Ossanna wrote a parallel implementation of nroff for the C/A/T, dubbing it troff (for “typesetter roff”). Unfortunately, surviving documentation does not illustrate what requests were implemented at this time for C/A/T support; the troff(1) man page in Fourth Edition Unix (November 1973) does not feature a request list, unlike nroff(1). Apart from typesetter‐driven features, Unix Version 4 roffs added string definitions (.ds); made the escape character configurable (.ec); and enabled the user to write diagnostics to the standard error stream (.tm). Around 1974, empowered with multiple type sizes, italics, and a symbol font specially commissioned by Bell Labs from Graphic Systems, Kernighan and Lorinda Cherry implemented eqn for typesetting mathematics. In the same year, for Fifth Edition Unix, Ossanna combined and reimplemented the two roffs in C, using that language’s preprocessor to generate both from a single source tree. Regards, Branden