Sort of unrelated, I had an idea earlier today about your editor, Toby, that feels interesting. I think I mentioned this to you briefly a while ago, but I think it would be wonderful if you could embed your editor in any page with the diagrams.
So say you have your planet simulation diagram in an essay/web page thing. There might be some kind of button attached to that diagram that when you click it opens up the editor inside the web page. I'd imagine you'd still be able to see the rest of the page for the most part, but the diagrams would have the editor surrounding them.
For readers, this would be a cool, low-friction way of playing with the diagram in a way the author didn't necessarily intend. They could change colors and parameters, change formulas, add their own notes, add new planets, etc. If the author was nice enough to break their diagrams into components, then all those components could be available for the reader to use in their exploration. I could imagine all this would make for a pretty magical demo as the editor fades in around the diagram.
If the results of editing diagrams in the context of a web page were persisted, then this interface could even be the main editor the author uses, making diagrams in their web pages and hiding the editor when they're done. To me, this goes toward fixing the annoying problem I always have that whenever you want to e.g. edit an image in a web page you're making, you have to use a completely different tool (photoshop) and in doing so lose all the context of what the image will look like in its intended environment, flipping back and forth between your tools until it looks right. It would feel much better to edit in context. And the symmetry between reading and writing implied in an author using the same tools that the reader is using to explore is very pleasing.