Drawn with burnt oak twig charcoal. Surface feathers, avian landscape. More of the body is involved (arm and shoulder muscles, esp.) when drawing larger (18 by 24 inches); moving the arm in broad strokes. (In contrast, drawing small, as I do when using a gel pen, is a little like drawing on a computer screen; the eyes get fixated on details, the muscles around the neck and head get tight.) Twig charcoal has highly irregular surfaces, so you can use different sides and edges to make different marks. Bits of charcoal sometimes drop off as I drew.