Ken ShirriffThe Computer History Museum has a presentation tonight on the history of computer dating: "Algorithms of Love". I made a special punch card for the event. It wasn't easy to make this card so I'll explain how I did it...
To make the heart, I had to figure out the right sequence of characters to form the hole pattern. Inconveniently, some holes don't form valid characters, so I had to "multi-punch" in some columns. This worked for one card, but the keypunch can't duplicate multi-punched cards.
Not a Spring Onion@kenshirriff
Would a two-pass approach have worked?
First duplicating a card with one pattern, then punching another pattern on top of it?