I've been searching through books and the internet for the diagrams of other artists that have tried to break down the very complicated human head into simple ideas. I thought these three lined up next to each other looked especially neat.
Here I applied the Reilly diagram to my general model's proportions and tried to shade it simply. I could not get it to look right.
So I tried applying it to a specific head. I went back to the first Bertillon card I traced back in July. I like the way it worked out. Long lines.
and it finally sunk in that the side of the head is flat.
Trial and error, variation and selection, and design - Tim Harford at TED