Drawing requires much looking, much getting to know why (in this particular case) the branches of the tree meander hither and thither through space, getting to understand what is going on. A drawing or a sketch doesn’t have to be perfectly accurate, this is not what looking or observation is about, no, what’s important is what you learn from looking and drawing, what you learn about the thing you are studying. (Afterthought: and possibly yourself too.) This is a pen and ink drawing / sketch using a new fountain pen just received postage free from China and it cost less than £4 sterling!!! But it’s just as good as the more expensive fountain pen I bought from Japan. And it’s much better than the constantly flooding Rotring Artpen.