I think these are also sometimes called "small multiples", no?

(might be nice to add to make it easier to find later for people searching for that term)

Yes. Thanks for the suggestion!

I'm assuming this was inspired by the question Toph and I had while working on https://observablehq.com/d/a1ce419a2a2c5d6d? In which, the outer axes are quantitative and not ordinal/categorical like yours. In that case, would the example still be considered "small multiples"? Both labels probably still apply?

It was! But here the axes are quantitative too—it just happens that I used regularly spaced numbers. Re: the last question, I'm all in favor of freedom: call them small multiples if you feel you want to do so… as you can see I'm not qualified to be an academic ;-)

Rewrite this to use a render function instead of an image?