And no, I am not talking about the ones you fly in….Chances are there are walls around you right now. Think about how flat and straight and perfectly vertical they are. Now realize that there is nothing that flat and straight and vertical anywhere on the head.
You may have heard about the planes of the head. So here is a simple way to think of them.
This a ruler. I am using it here to show something very straight.
And here is a profile of my friend and plaster cast, Fibonacci.
If I put the ruler against his profile you can see something interesting….nothing matches that perfectly vertical ruler. Everything on the human skull does this interesting “back and forth”- up planes and down planes.
If I put the ruler against his forehead, it tips back away from vertical- and thereby catches more light so it is an “up” plane.
If the ruler tips away from vertical the other way and follows what you can think of as an “undercut” then this area is a “down” plane. Catching less light from above. Like this lovely little area here between the eyes- the glabella.