Affordance(+) mapping(-) Mechanical Pencil

Unlike most mechanical pencils that have the release buttons at the end of the pencil, this one has it on the body. However, this unconventional design is very intuitive since this button has a positive affordance for pressing. It does have a poorer mapping than the conventional ones though, since the lead goes straight out of the pencil while the button pushes perpendicularly to that direction.

Done