I drew this in the summer, and it actually took two days. I must say I'm in love with gradual building of form with hard pencils. It lets you have a steady control of texture and to look very closely at your subject. And unlike working with a pen that quite quickly constricts your use of gesture, every time you step up to a softer/darker pencil you have another chance to work gesturally. It would seem two days on a small sketch like this would suck the life out of it, but to me this looks quite alive.
Maybe it's simply that I had such a soft spot for pen and line work all throughout college that I finally exhausted my use of it of course, but I think there really is something to line drawing process that is stifling. And it's the overbearing contour. No matter how much you try to build sculpturally, you get this containment effect. I still use contour of course. After all I think like a draftsman, not really as a painter: contour line is here to stay. But I am much more welcoming of it, when it's in 2H or 4H graphite. It lets the things you draw breathe.