I designed it for a competition which was held by a company. There, we were asked to design a pencil and to suggest trade ideas, what should be done for prime costs.
My advice was as follows: Produce a mechanical pencil. Produce the pencil with two buttons; one on the top, one at the bottom. Produce the body transparent and produce it such that; inside the body, one can put a paper. The owner of the pencil will have a picture printed in appropriate size and put inside it. Or if he/she wants the pencil be self-coloured, then he/she will put a construction paper that is desired colour. Thus there won't be any problem about what colours should be produced, which one will be sold or not, do people like the top button or bottom button. In addition, produce an accessory that named "eraser cutter". It will be a gadget just like a hole punch. When the eraser in the top button give out, the user will cut a ordinary eraser with this accessory and put it in the top button. And thus, this will be a marketing strategy too.
My name suggestion for this pencil is: By the inspiration of tea kettle, up and down buttoned customizable pencil. In short "up&down personalizable".