Ten columns of an IBM card, twelve rows each. Punch the holes and the
character prints along the top, the way a keypunch interprets a card as
it goes through. It arrives spelling HOLLERITH.
What follows is a grid of 120 checkboxes, twelve rows by ten columns,
making up a punch card. Each is labelled with its column and row number.
Ticking the right combination in a column spells a character. There is
nothing here you need, it is a toy.
Print at 100 percent, do not scale to fit. The card below is 7 3/8 by
3 1/4 inches, which is the real size. Cut along the outline, and take
the corner off along the diagonal.
12110123456789
How it works
Each hole is a checkbox, and the decoding is done by CSS asking each
column which of its own boxes are ticked. Sixty rules, one per
character, generated from the IBM 029 keypunch table.
Rows 12 and 11 at the top are the zone punches. A letter is a zone plus
a digit, so A is 12 and 1, J is 11 and 1, S is 0 and 2. Digits are a
single punch. Everything else is a combination involving row 8, which is
why the punctuation looks arbitrary until you have the table in front of
you.