21-Second Upside-Down Grayscale Face Scribbly Warm-Up

Done as part of a practice session with poses of 21 seconds in length.

My current goal is: Improve my understanding of the forces of the facial skull, in terms of my facial anatomy.

Here is my latest warm-up scribble of a grayscale upside-down face. It's really authentic in look, and feeling, because it helped my completely and totally loosen myself up in my hand. It forces me to be perfectly fine with making mistakes in my forces of my facial skulls.

What do you all think of my progress so far?