Advanced Drawing class, 1997-ish. Jim Pink's class. Three 5-minute sketches from a live model. Paint, charcoal, conté crayon on butcher paper. The objective was to focus on the lighting. To really examine lights and darks and create the shapes using lights and darks, first. An exercise in seeing things differently than how we normally look at something.
Every now and then, I think about that exercise as an application in day-to-day life. Looking beyond the first impression of something, taking the time to examine and think about it differently. To look at how light and dark define a shape almost better than the shape defines itself. It's a pretty cool exercise to apply to different things, and people. You should totally try it. :)