One topic that came up in recent workshops was how to attach a point to a polyline so that it stays on that polyline, and can slide from one segment to another.

Here is an example of a custom goal to do this. When you open it, you will need to change the referenced assembly location to your own local copy of KangarooSolver.dll

This can also be used to attach multiple polylines to each other in a sliding net, by attaching the same point to both.