This is a great video, Morgan. You point out that it's best to usually have a single light source and have strong light and shade, we don't want references with all sorts of bounce lights/reflectors messing up the shadow pattern. I was thinking that you certainly have paintings with very little shadow, where the image is basically flat shapes of color with a bunch of ambient light, without strong light and shadow patterns. The first ones that came to mind from your book were "Blossoms" (pg 144), "A Helping Hand" (pg 151), and "The Woodlands" (pg 170). Turns out, I was wrong! Even those paintings still have good light and shadow: in "A Helping Hand" we see a head turned down to the ground that left part of the face in shadow, and another head turned up and shadow under the chin and ear, and even the landscape itself has areas dropped into shadow, even though IMO the landscape looks like it's a little foggy and there's probably a lot of ambient light filling in shadows. Maybe I'm wrong, but those lighter shadows on the trees in the middle ground, and the very soft/lost edges on the hill in the distance indicate a somewhat foggy day to me. So even though the light looks softer, foggy, and more diffused with more ambient light, there's still a clear shadow pattern. And it still all reads correctly. So, big lesson here: spend more time getting good reference with a strong light and shadow pattern. It doesn't have to be super contrasted like a baroque painting, but it shouldn't be all washed out with flat shapes all over the place or confusing lighting from some types of photography.