Spawning convex polygon from code

There is example of puzzle game in unreal engine 4, where field spawns from code 9 squares and if you click them score goes up. I want similar system, but I need to spwan not squares, but convex polygons.

So question is: I somehow from code get N vertices, representing vertices of convex polygon. How do I spawn such polygon in the world from C++ code?

I found two ways: subtract parts from square shape with subtraction tool and making a skeletal mesh.

Using subtraction tool from c++ seems a little bit weird.
Making skeletal mesh for just polygon seems like an overkill.