In the spirit of becoming your own teacher, the final exercise is up to you. What usually informs my choice of homework is what we have been doing in class and what we will be working on in the next session. That puts us in the portrait/figure realm. I’ll attach a few images that may interest you if you want to follow up on the portrait practice you’ve had in the past two weeks. I’ll also attach a couple of figures with distinct shadow patterns for those who’d like to warm up for the model we’ll have this coming week.
It’s all about seeing in layers, right? A useful exercise would be to paint the shadow pattern by itself, with no pale first layer at all. This reveals the role the middle values play in describing light and volume.