What are these little keys/teeth/pins for?

Question

I had these in my mystery keys stash and I can't work out what they are. 

Answer 1

Favourite answer

Those are drive points sprigs.  They are put into frames to hold the artwork and backing in place.  the picture below shows them all hooked together for placement in a drive point gun, like staples, but the gun shoots them along the flat backing and into the frame. 

Answer 2

They look like dowel pins to me. Carpenters/joiners use them to lock joints in wooden frames. They superseded wooden dowels for this purpose.

Answer 3

They look like sprigs for holding things into picture frames.