/ic/ - Artwork/Critique

Not OP, but I have a question regarding loomis as well.

I'm reading "fun with a pencil" but pic related page makes no sense to me. So the browline should be the middle of the ball, the second half of the ball is the next section, then the next two parts go off the ball, and the very bottom of that is the chin?

Or the browline is the middle of the ball, halfway between the browline and the top of the ball is the hair line, halfway between the brownline and the bottom of the ball is the nose line, and an extra section going down is the chin? If so, why in pic related does the noseline look like the bottom of the ball? Perspective?