I did this quickly to help explain something to a person on the Tutorials & Critiques FAF board. It isn't perfect at all. I have a tendency to largely ignore the head circles I draw when I start, which isn't great, but I understand the concepts they are telling and that's the main thing. Also, I drew it quickly in large part because I'm recovering from shoulder surgery and am in substantial pain.

Anyways, I'm trying to point out how the eyes are at the very center of the head. The guy to the bottom right with the club, he doesn't follow this, and I intentionally drew him with a small forehead and massively extending jaw, because that is the mistake the person I drew it for keeps making. It really only works if you're actually drawing a neanderthal.