Have you ever cut a rubber/eraser? Well, it probably depends on the type, but it generally is very amazing - at least to someone like me who likes to fiddle around with things.
This one has a long history, it must be ancient, really. And one can see the holes where we used to stick the pens in. (As I found out when cutting it: In some of them there're even pieces of lead left that broke off.
I think the star's points will break off rather soon when it's used, but nevermind. I thought it was a good way to honour such an old and faithfull companion. :)