Parametric Quoins Script Ideas

Hello Grasshopper Community,
Recently, I’ve been developing a script to model quoins on historical buildings. I’ve managed to isolate the vertical convex edges from a ClosedPolysurface (representing the building’s structure) and have organized these edges along with their corresponding vertical surfaces. However, I’m struggling to find an effective way to model the quoins themselves. I would appreciate any suggestions or ideas on how to achieve this. Any input would be greatly helpful.

Here are some goals I am trying to achieve:

  1. The Quoins are flat on the horizontal edge, and natural/have small curvature on the vertical edge.

  2. The height and width of the Quoins are random within a small range. For example between 1.5 to 2.5 feet for the height and 2 to 3 feet for the width.

Thank you!
Rui

Here is an image that shows what I am trying to model.

Below are my rhino and grasshopper files:
Quoins Script for help.gh (35.4 KB)
Quoins Modeling.3dm (174.5 KB)