Just came across an interesting article on curvature continuity: it's a subtle, but very elegant, version of rounded corners. I think this would be a terrific addition tio AD's feature set (AI requires a $50 plugin to do the same), and I'd love to see this implemented into Designer, perhaps as options on the Curve and Rounded Rectangle tools. Cheers.
The article:
https://hackernoon.com/apples-icons-have-that-shape-for-a-very-good-reason-720d4e7c8a14#.eckdl9bhg
The AI plugin:
http://www.pixeology.com/Spiro/features.html
Biezema got a reaction from greyscale in Curvature continuity