This is part of my ideation process, I'll take a sketch and redraw over and over again. I do it to begin with and then I'll do it over an established sketch. Formstorming is tiring but absolutely vital - wether it's a graphic design project or a digital painting project. Small variations like these can change the basic image substantially. Doing as many as I can is key - 50 to 100.
"If you blog it, you'll regret it. If you don't blog it, you'll regret it. You'll regret it whether you blog it or not."