RT @hughmason
@mengwong I'm just old enough to have written some of my first programs on cards. It was common to mark a diagonal stripe on a deck to show the order and edits. Wikipedia notes that columns 73-80 were sometimes used for a sequence number for sorting https://en.wikipedia.org/wiki/Computer_programming_in_the_punched_card_era
@peterdrake I remember this. Oh dear!