I do have a passion for mechanical/and propelling pencils I wont bore you with all the ones we know such as Yard O Led but just a couple of my favourite more unusual examples. One is 9ct gold in the form of a bullet probably intended to go on a watch chain. It has a push pull action to expose the propelling pencil. The other is made from some sort of thorn or carved wood in the shape of a hook again I suspect for a watch chain.