So I tried to create a demo of this (the second paragraph) on CodePen[1]. While it works fine for shallow angles, it leads to some unsightly loops when tracing

So I tried to create a demo of this (the second paragraph) on CodePen[1]. While it works fine for shallow angles, it leads to some unsightly loops when tracing tightly acute (deep? sharp?) curves. I assume there's a way to mathematically identify the points that form these unwanted loops, so they can be discarded when drawing the parallel curve - but my maths skills aren't up to the job this morning. [1] - https://codepen.io/kaliedarik/pen/jOxqJjm https://codepen.io/kaliedarik/pen/jOxqJjm