Today, I revisited the chair-drawing exercise. I was instructed to draw the negative space found "behind" the chair. Unfortunately, I decided not to follow those instructions. I found that however hard I tried, the angles just would not line up. It was much easier for me to draw guides for the legs and dowels. I hope it was just the nature of the structured subject that caused me to, in the vocabulary of Drawing on the Right Side of the Brain, use my L-mode for this sketch.
I'm excluding other attempts and just calling this my "second" try: