I've found Bostock Observable to be a fascinating and inspiring platform since the outset in my limited experiments with it. I wish they'd give it a name that isn't a well-known design pattern that it implements, because I end up having to call it "you know, Bostock's thing" in conversation.

However, I definitely don't want to have to type "<script id="2" type="module" pinned>" in order to calculate 1 + 2, and I don't want to have to scan past that in order to find the actual calculations. So I guess I'll have to keep being inspired by Bostock Observable Notebooks 1.0, which I can keep writing in GitHub-flavored Markdown, because it's free software and already checked into Git.