algorithmic modeling for Rhino
It generates the set offset curves and some of them will inevitably be junk. I 'discover' the junk by inserting one point on each curve and check if the distance to the closest point on the original curve, is the actual offset distance, if it's not due to junk geometry it's culled.
As Nik show it's possible to give it geometry that will fail.
Some references to give context to Morten's strategy:
Mention of image-based strategies: