One of the most challenging exercises I had to do for my first painting class was a series of 20 self-portraits. We had to do one every night for 20 days in a row. It was challenging because I didn’t know what I was doing, it took at least twenty minutes to set up all my oil painting stuff every night, and I went on vacation for a few days in the middle of these 20 days. It’s a good thing I went to Mexico on a bus and not a plane. The airport would not have appreciated my jar of gunky turpenoid very much (because it’s toxic and flammable).