Sand and Shadows

I'm still working my way through the nature pictures I thought would be interesting to draw. I bit off a little more than I could chew today with a sand dollar that had both sand and shadows. Both seemed to call for the same shading technique, and I'm not convinced I pulled it off.

I did get to play with my paper stumps and tortillions, so that was a fun bonus.

Original picture:

My rendition: 

I did get at least some 3D feel to it, and there are definitely some different colors in the shadows. 

It's getting less stressful to sit down and draw. I'm starting to mentally break objects down into their component shapes.

Nature observation: it was interesting to see that the markings on the outside of the sand dollar were not perfectly symmetric. Apparently even nature needs to practice its drawing.