<http://www.theregister.co.uk/2018/06/21/how_a_tax_form_kludge_gave_us_25_years_of_pdf/>: [In 1985] ... both Apple and Adobe wanted to show off the LaserWriter's abilities with some sample files. Warnock thought it would be great to have the printer producing something complex but familiar so he personally hand-programmed an IRS tax form in PostScript. ... all those boxes and form fields required Warnock to code in lots of subroutines and utilities. The page took 2 minutes 45 seconds to print. Jobs was horrified at how slow that was. ... His new version of the IRS tax form printed on the LaserWriter in 22 seconds. In other words, by abandoning all the programming-language constructs (subroutines, conditionals, looping etc) in PostScript and just writing out a straight sequence of imaging commands, the code ran a lot faster, even if it was bigger. The article mentions the release of PDF 2.0, which is now being managed by ISO. Unfortunately, unlike Adobe, ISO do not make their specs available for free.