Offset and Extrude open meshes in GH

I have tried this for longer than I would admit… My guess is that I either know GH too little, or that it actually is not possible to offset / extrude an open mesh (unless going much more hard core).

Please see the attached definition of me trying to make Offset mesh work.

Edit: For the offset-function I would like it to remain open (I am not looking to thicken it) and for the extrude-function I would ideally like it to be closed. (114.4 KB)

Not sure this help, there is a plugin that can do this.