There is a unique quality that can be illustrated only with line. It's hard to describe but it is akin to the interplay between light and shadow on a brilliantly sunny day. Once hue is introduced into a piece this quality is impossible to achieve. It has nothing to do with the thickness or curvature of the line. The closest thing to it is rhythm. The banging out of a meter of light and darkness. I enjoy this subtle dance between positive and negative spaces and always try to maximize it in my work.