Mark sez, "The recent post of the CARDIAC Unboxing [ed: the CARDIAC being a cardboard teaching computer that Bell Labs released in the late 60s] made me poke my father, who has written a CARDIAC emulator that actually looks like the real CARDIAC, to put together a webpage with the source of it. Both his childhood and mine were definitely influenced by this little wonder out of Bell Labs, so for those who can't get the cardboard variant, here's the software one, along with a scan of the original CARDIAC manual."
CARDIAC: (CARDboard Illustrative Aid to Computation)
(Thanks, Mark!)
