Hatching entails build up parallel marks of different density. Experiment with horizontal, vertical and diagonal hatching or a mix of all three. It's been popular with artists for a few years, originating in historic cultures. Among the earliest surviving pen and ink drawings will be the Abduction of Briseis https://collinxdmxj.getblogs.net/67550289/the-basic-principles-of-ink-pen-drawing-techniques