This is called a Sierpinski Triangle. It's a fractal shape of inscribed triangles. Each iteration increases the number of triangles. It's some pretty neat stuff and I'd recommend looking into it! You can increase/decrease the number of iterations and also if you press space the triangles spin - why? I don't know I just felt like adding that.
All of the code was done by me and it's all done in pen. Feel free to look inside to see how it works :)