A million skritches, each one black as pitch, adding up to gray. That's cross-hatching for you. It's the white page that does it; no matter how many skritches you put down, the blinding white shines through, and when you pull away, it's gray. If you started out with a black page, things would be different. You'd skritch and skritch and it would be like you had no ink at all. That must be a comfort of sorts.