Drawing robots is a good exercise when one is in a sketching rut. Anatomy is not really an issue, however making an image that is interesting is an issue. Note the hatching on the "head" of the robot (patterned after R2D2, naturally), this happens when the artist is obsessed with approaching projects in terms of comics. The instincts become honed (and limited) to translating an image for reproduction with a pen or brush and ink. It's something which those of us raised in the last century tend to cling. A pencil is capable of fairly subtle shading, yet I choose to ride up on its point and treat it like a crow quill nib. Bizarre.