How to make a border with lots of edges?

Hi everyone,

At first I want to say that I’m not an expert neither in PDEs nor in FreeFEM. I would like to build a 2D mesh: the external border is a square (ez to do), but the internal border is a polygon with lots of edges. The examples I found in the documentation where always building a mesh from an explicit sequence of borders like:
mesh Th = buildmesh(C01(-n) + C02(-n) + C03(-n) + C04(-n) + C05(-n));
But in my situation, I can’t sum the borders like that since too much borders and I dont know before execution how many there will be.
Maybe I didn’t see something, again I’m not used to FreeFEM :slight_smile:
Have a good day

see 3.2.3 Multi-Border in the doc.