What do we do when things are hard to describe? We start by sketching out the roughest shapes to serves as scaffolds for the rest; it does not matter very much if some of those forms turn out partially wrong. Next, draw details to give these skeletons more life-like flesh. Last, in the final filling-in, discard whatever first ideas no longer fit. ...Until you've seen some of the rest, you can't make sense of any part.