I found "Sometimes computer printers with a
typewriter-like
moving type head print boustrophedon if set up wrongly."
Which old printers might've done that?
Not sure exactly, but:
Epson dot matrix printers used to advertise "logic seeking" and
"bi-directional printing". They reversed the lines internally, but an
older printer with no buffer might expect to be fed lines alternating
forward and reverse, so it could print them in proper order when the
head alternated forward and reverse on successive lines.
De