I suspect this had a two-step teaching process for neophytes... First, they'd play with the cardboard machine and get a feel for assembly programming, instruction processing, memory, etc. Once then, after a bit more hacking on things like Star Trek or 4x4x4 tic-tac-toe they'd set out to write an electronic version (virtual machine!) of the cardiac "computer". Debugging that process taught all sorts of relevant things.
And it vaguely felt like a PDP-8, and I suspect it also felt like whatever very early minicomputer that was available.
Related, from 1959, many years before CARDIAC:
PAPAC-00 A 2-register, 1 bit, Fixed Instruction Binary Digital Computer
https://longstreet.typepad.com/thesciencebookstore/2010/11/a...
I was given one of these by my eighth grade science teacher, ca. 1970. I still have it. It helped spark my interest in computers.
> Fig. No.5 Flow chart of repairing a flat tire
> Start: Are you a girl?
man, I was not prepared for that lol
I'd love a SUBLEQ mechanical computer with Eforth outputted into a teletype.
This one is higher quality (https://content.instructables.com/F84/WG7G/K2XU5LKV/F84WG7GK...) and it's all kinda pointless without the "machine" https://www.instructables.com/CARDIAC-CARDboard-Illustrative...
I didn't get mine until about 1979 or 1980. Still have it, though.