Another way to shade a region in 3 dimensions will be to draw traces in addition to each other. Using this method you boost the quantity of black and so make a shadow. Hatching and cross-hatching are essential techniques in pen drawing, used to create shading, texture, and depth. https://how-to-draw-with-ink-pens24567.bloginwi.com/70458375/facts-about-ink-pen-drawing-techniques-revealed