Hah, that's really nice! I've been working on an editor for setting up Box2D scenes for the last month or so. I know there are a bunch of them out there already

Hah, that's really nice! I've been working on an editor for setting up Box2D scenes for the last month or so. I know there are a bunch of them out there already, but it seemed like a fun project. No Tcl/Tk for me though. I'm writing it as a web app, but in C++ with wasm/webgl and using NanoVG[1] for drawing. I saw a comment here about undo/redo and I think it's a must have feature for something like this. I implemented something based on the command pattern first, but ended up disliking the amount of code needed just for undo. I eventually tore all that out and built my state model on the excellent immer[2] library. [1] https://github.com/inniyah/nanovg https://github.com/inniyah/nanovg [2] https://github.com/arximboldi/immer https://github.com/arximboldi/immer