What is the reason for sewing triangles onto the ends of a hammock? I see that they are on some hammocks that places sell (Chameleon, Sparrow) but then there are hammocks without the triangle on the ends (Darien). I see that many people link to Xtrekker's video on how to sew a bugnet onto a hammock, and his has a triangle. However, I wanted to know thats the main purpose for having them.