I love this image... my kinda thing... but... I've one niggle with the presentation.
Given that this image is ALL about symmetry and shape I would suggest removing the shadow framing as it detracts mightily (in my eye) to the rest of the image.
I's also suggest that the shadow is way to dark for the image but in this case I would remove it completely.
This is NOT due to a phobia of such framing... I use it myself quite a bit, but in this case I think it does significant damage to an otherwise beautiful piece of art.
mmm... no soapbox emoticon... so ...