Sketch drawings use similar techniques, although with pencils and drawing sticks continuous variations in tone can be achieved. For best results the lines in a sketch are typically drawn to follow the contour curves of the surface, thus producing a depth effect. When drawing hair, the lines of the sketch follow the direction of the hair growth. | Sketch drawings use similar techniques, although with pencils and drawing sticks continuous variations in tone can be achieved. For best results the lines in a sketch are typically drawn to follow the contour curves of the surface, thus producing a depth effect. When drawing hair, the lines of the sketch follow the direction of the hair growth. |