On 2023-01-11 12:44 a.m., Joe Harrington via Contra Callers wrote:

I heard recently (I believe from Angela DeCarlis) of a mechanical sorting system based on the Jacquard loom concept that became the Hollerith punched card system.  I've never seen it in use.  Does anyone do this?

See https://en.wikipedia.org/wiki/Edge-notched_card

[Ah, Jeff Kaufman beat me to it.]

Figure out the ten or so characteristics you might want to sort on.  For example, easy, medium, hard, bouncy, flowy, separates partners, sweetheart (keeps partners together), etc.  Take a stack of cards and drill holes near the bottom edge, one per characteristic (you can drill a stack of cards if you sandwich them between wood and clamp them).  Now, on a given card, punch out the rest of the paper between the hole and the edge of the card for each hole the card DOESN'T match.

Alternatively, you could punch out the margin when it *does* match (which would probably be less work). Then in the selection procedure, the cards that fall out (as opposed to the ones that stay on the needle) are the selected ones.

 [...]

Good hole alignment and clean punching would matter, I think.  If you are a real dance sorting fanatic, you could get like 30 holes around the card edges, but that would limit the writing space.

Back when I was young and had lots of time (and no computer), I made a deck of edge-notched cards to 'play' the game Mastermind:
https://en.wikipedia.org/wiki/Mastermind_(board_game)

(4 pegs of 6 possible colors, so 1296 cards, each with 24 holes and 4 notches.) As I recall, during the selection procedure, cards with a notch at the selected hole (which *should* fall out) would sometimes 'stay on' the needle just from friction with the neighboring cards. So I'd have to jostle the deck a bit to shake those loose.

Also, V-shaped notches increased the chances that a card would fall out when it should.

One way to avoid these problems is to have two opposite sets of holes, with complementary notches. In the selection procedure, you use two needles, placed in complementary holes, and you pull them apart to separate the cards you want from the ones you don't.

-Michael
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