Although this looks like New Year's resolution fervor, the timing for this JSVB post is coincidental. I've been going through a long slow patch of work, so sometimes doing artistic drills helps me to create fresh material.
This drill is to make value changes from deep shading to medium to light using hatched lines. In animation, I very seldom used hatched lines since every line that goes into the drawing must be accounted for and animated. Those were the old days. Now that I don't have to worry about line counts, I have begun to study how to make effective hatches with lines. Drills help to tighten up these otherwise vague skills.