Skull WIP 1

I've read that if you want to understand how to draw people you should know how to draw the bones beneath the skin.  Since I'm mostly focusing on heads at this point, that would mean the skull.  So, I've decided to draw a skull from photo reference.  Here is my progress so far:

Of course, this means that I now have three WIP's going at this time; Tom Waits, Ben Brand, and the new Skull.  I'm not sure when I'll get to the Tom Waits one.  I've become so focused on drawing on the computer that drawing with actual physical media barely crosses my mind.  It shouldn't. But that is just where I am.  I'll finish the Ben Brand piece.  That's just a matter of there being a part that is confounding me at this moment (the barbell).  Who knows when they'll all get complete.  Life takes priority...as much as I wish that it didn't.