I wasn't quite sure how to apply shape to simply improve the previous composition, so instead I decided to explore how it would change it. While the solid shape does create nicer balance and it does still vaguely resemble an arm, the sense of motion is almost completely lost. I think this could be recovered with some clever shading, possibly in a cyclone like pattern, but as it is I'm not sure that shape improved the composition.
Is this a good/useful/informative piece of content to include in the project? Have your say!