I love the shading in these sketches from David M. Friend.
©David Michael Friend. You can see the entry for this piece on David’s blog:
Exciting News: we now have www.trainfaces.com – for now it just redirects to here, so you don’t need to do anything 🙂 Please spread the word about www.trainfaces.com and get in touch if you want to share work (email@example.com). Twitter account coming soon!