IBM Proprinter

It arrived in 1985 as a nine-pin machine doing roughly 200 characters a second. Technically unremarkable, but the construction became a textbook case in design for assembly: parts dropped vertically into one another, snap fits replaced screws and wiring harnesses, and the component count was less than half what competitors needed. A robot could build the entire printer, and human assembly time was measured in minutes rather than half hours.

Its other legacy was the escape codes. Where Epson's ESC/P was already the industry standard, the Proprinter's command set became the second one, and for a decade afterwards every dot matrix printer worth buying had a menu offering "Epson" and "IBM". Choosing the wrong emulation announced itself immediately: the page filled with escape sequences instead of text.