Rubber/ink stamps for planning out factory designs on paper, but more consistently and... automated... than drawing by hand. Ideally, sized to fit common graph paper dimensions, e.g. 1/4 inch per tile edge. I'd love to be able to stamp down some non-specific assemblers, and add an item icon for the ...

I had assumed the tick-based belt animation was already being done - should be a pretty significant gain in performance for large factories if they've been updating their frames individually.

Good luck with the various belt segment considerations