/ic/ - Artwork/Critique

i've been experimenting around with different methods of constructing faces/heads, using a perfectly circular cranium like in Hale's proportions as the foundation for it; the infographic in the lower right is the current standard i'm using

one thing i can't figure out, though, is how the hell the guy with the open hand's head works. i can construct his face with relative understanding, but i've been staring at this dude for like 20 minutes trying to figure out how the to illustrate the depth of his head. in theory, the back of his head shouldn't be too far from the central purple circle, but in reality it's over half the height of it. i'd think it's a flaw with my approach (it may be, i'll try to do more from this angle), but i did similarly foreshortened heads and didn't get this issue from it. whaddya you guys thing?