I actually make a diagramming library for the web, called GoJS, so that other programmers can quickly add interactive diagramming capabilities to their web apps

I actually make a diagramming library for the web, called GoJS, so that other programmers can quickly add interactive diagramming capabilities to their web apps: https://gojs.net https://gojs.net So I make all kinds of diagrams, mostly as demonstrations. When developing a library itself, especially one where there are phases (Graph Objects must measure themselves and their parts, and draw in a certain order, and not more than they need to), state machine-style and flowchart-style diagrams are awfully helpful.