Because they always work problems out with a pencil.
Pencil-vania.
What did the pencile say to the other pencil the answer is........... Your Looking Sharp
Gristle While You Work!
Hnng. Aaaaaaaah. Like that. I'll show myself the door.
He worked it out with a pencil!
When you fix one problem, 38 more problems pop up.
He works it out with a pencil.
Poop-ease
Gee I'm a tree!
Because they are always multiplying.