Here is a porcupine pen holder papercraft I made. Actually there's no porcupines in my country so it might not actually look like a real one.
I made this using 200gsm paper and I glued black construction paper at the back so that the inside of the porcupine will be black. It won't close properly because of the thickness. Maybe a 100gsm paper would do if you're going to do it this way.
Note: Attach (1) and (2) first to (3) then close at the bottom.
Template and more pictures after the cut.
Just recently found out that I can use google docs for pdf files. From now on I will upload my templates there.