Polygon Shelves on a curved surface/Curve / Pattern

I would still like to need a shelf on a curved wall. I tried with Rhino to somehow turn on the control points and then offset a surface, curve and try to take every other point and connect them individually with polylines. Unfortunately it’s not clean and I don’t understand why not.

Can someone help me with scripting in grasshopper?

how to get this pattern built along the wall?

Regal dekorativ.3dm (8.4 MB)

Here’s one way how you can create a zigzag wall in Grasshopper:

zigzag.gh (16.5 KB)