I'm working on a sewing pattern software to make patterns with code. It has a bunch of useful features like chopping up the pattern into a PDF for printing. But the thing that really made this software nice to use is the timeline I implemented, where you can go back and see how the pattern is constructed with each segment. It makes debugging so much easier. I have it so you can put different curves into groups, so you can see how just the sleeve is constructed, for example.

I will definitely consider adding timelines to future software I make, it's an awesome feature.