Hello, 2391. Congrats on finishing a tough challenge! Here's some feedback:

Having looked at your boxes, I think you pretty much nailed the challenge. Your convergences are mostly correct (converge away from the viewer). Your inner corners are also mainly within perspective. You've also drawn boxes in a good variety of orientations and your linework is confident. There are a few hatches that are wobbly, but that can be fixed easily by remember to start your line on the dot (like the superimposed exercise from Lesson 1). Comparing your first and last boxes, it's clear that you have a good understanding how boxes sit in 3D space.

The only thing that I might suggest would be to try drawing boxes with orientations that have shallower forshortening. Not only does this increase your comfort with drawing objects that are human-sized or far away but it also prepares you for the lessons ahead where shallow forshortening is more relevant (since the objects being drawn are not overly large).