I've done a few diagrams in PlantUML, which were better than nothing, and better than using a vector editor and doing it by hand, but there's a constant low-lev

I've done a few diagrams in PlantUML, which were better than nothing, and better than using a vector editor and doing it by hand, but there's a constant low-level frustration. One, if the authors didn't think of something, you can't do it, and two, if the layout engine makes bad decisions, it's truly tedious to instruct it otherwise. It also starts like a mile-long freight train, and goes about a hundred yards. I have no idea what it's doing for the first five seconds, but it isn't compiling my diagram. I've switched to using Pikchr, which has never met an abstraction and doesn't want to. It uses a Logoesque layout language, invented by Brian Kernighan as PIC, and reimplemented with improvements by D. Richard Hipp. He uses it for all the railroad diagrams in the SQLite docs, as well as many more UML-like diagrams in the Fossil docs. If you've found yourself cursing softly at PlantUML/Mermaid/dot, because the icons just won't go where you want them, I strongly recommend giving Pikchr a try. If you want to diagram something which was never contemplated by Booch and friends, there's no second choice.