Hot to generate recursive shapes like geokone.net using GL.Begin?

http://app.geokone.net/ is an open source javascript app for generating shapes like this:

It's hard for me to go through it because it's a lot of code, what is the general idea?

also, I need those shapes as GameObject with polygon collider around them (anything from 0 to 20 of them on the screen at the same time, could be different shapes also), is it even possible with GL?

would GL help me? I think GL would be fast for just 1 shape or something (as it's using recursion), but for what I want, I think drawing them in real time to a texture, then using the texture as a sprite would be faster (as I can save the sprite for shapes that are the same), or maybe I should use a shader? any other method that you can think of?