I'm trying really hard to figure out how to do this, but I can't seem to get it to work properly. I have the frilly curves on the left side of the thin line. I'd like to use that line as a form of mirror, and the nodes at the ends of the curve are snapped to the line. I have tried duplicating the curves, flipping and rotating them, and trying to snap them as well, but it is not working. I can't find any "symmetry" feature except in the Pixel persona, and I don't think I want to go there.
Am I looking at this the wrong way? Should I be doing something else to accomplish this? I'm making several more corner designs like this that require 45 degree mirroring.