Fancy Corners with Masks

[Acorn]

Good stuff, Acorn.
Looking forward to how you'll apply the lost outlines. I tried a number of things with 'Shapes' but didn't succeed.

Boy, this is the best I have managed:



Add back a Complete Stroke
1.Clone Masked Shape - Ctrl+K
2.Set Line Width to None
3.Detach Opacity Mask - Alt+O
4.Ungroup - Ctrl+U
5.Delete any White Mask Objects
6.Select all and Arrange > Combine Shapes > Intersect All Shapes
7.Delete all Black Mask Objects
8.Add in Line Width


The result is destructive so you need to keep the original.

Acorn