Wikipedia also has some information on https://en.wikipedia.org/wiki/Carole_Hersee

That's a great link, thanks. I was actually looking for an image of testcard 61 (at the bottom of that page), a copy of which I saw being used only a few years ago!

57 is interesting too; the black square in the centre is actually a hole leading into a box lined with black felt, to provide a black reference.

The generation and use of test cards and patterns is a surprisingly complicated subject; even in the digital age.

A close variation of test card G on that page is common in a long list of countries, as it came from a highly successful commercially available test-card generator, and the pattern has since been copied and modified all over the place:

https://en.wikipedia.org/wiki/Philips_PM5544

A popular test card in the US, which you can still see in some digitizations of black-and-white era recordings, is RCA's "Indian Head" card, named after the line drawing at the top for subjective sharpness checking:

https://upload.wikimedia.org/wikipedia/commons/1/1b/RCA_Indi...

I'm rather fond of that test pattern because it was usually generated by a dedicated piece of hardware that scanned a CRT beam across a metal plate with the image on it. This was to produce a more reliable source image than the more common practice of pointing a camera at a test card in the studio - and is an odd predecessor to today's test-pattern generators.

It's actually Noughts and Crosses ;-)

I think she'll still beat the inanimate puppet.

If she's 'X', then playing in the bottom-center square will put the game on the path toward a cat's game. Perhaps the puppet is strong AI, and she's trying to teach it that in some games, the only winning move is not to play.

The "X" on the board represents the exact center of the screen.

Christ, I'd forgotten how grim these were.