I am sure this has been discussed here, but I can't find it in the archives. It probably came up in the long-deceased Usenet newsgroup, as well, back when it had some life left in it. So I apologize for spanking a long-dead monkey.
Anyway ... A guy who writes a column called "The Research Doctor", found on a well-known radio industry website, is a fanatical collector of clocks. He owns hundreds (which, he says, is interesting when changing between Standard Time and Daylight Time!) I asked him if he was familiar with a clock or an alpha-numeric display of the flip variety. Not like the old digital clock radios, which flipped from top to bottom on a horizontal axis, and were very common in the 70s and 80s. Rather, he's interested (VERY interested) in the one I described to him: Each numeral flips from right to left, on a vertical axis.
A TV station I worked at in the early-70s used a monochrome camera, which was permanently focused on such a clock ... along with a readout of the current official Chicago temperature. The clock portion went through all 24-hours, as in miliary or European-style time. The temperature portion of the display also contained the alphabet, and a few punctuation marks.
I'd guess these displays were of the type used in airport terminals, before monitors and LED readouts became common.
Anybody know who made/makes them, what they're called, and how this feller might get ahold of one? For some reason, my brain remembers it as being a General Electric product ... but that might be a faulty memory.
