Yes that works, so let's get started!

Your box work has improved quite a bit throughout this challenge. Your sense of space and perspective, as well as overall line quality. You did a great job varying the size and orientation of your forms as well as the rates of convergences. You correctly applied your check lines to each page, and the benefits from this paid off in spades. You made some serious jump in quality relatively quickly in the process.

You are still having some issues with back lines getting skewed, but that is ok because uncomfortable has made this infographic regarding parallel lines in perspective. The first thing to understand is that parallel lines are all tied together and related to one another by the vanishing point. As its location changes, or a line shifts (which is an implicit change of the VP) then everything in the ensemble changes as well. This change is manifested in the angles between the lines. You can make this information actionable by learning to "step back" and view all of the parallel lines simultaneously. Often times students focus on one plane at a time making sure all the lines are right, then move on to the next plane with no regard to the lines previously put down. This is why we end up with multiple points of convergence instead of the correct one. When you can start to take into account all of the lines simultaneously things start to just slide into place. Now obviously this is way easier said than done, but if you begin to practice with this in mind it becomes more intuitive.

Now there isn't a whole lot to say here. You did your boxes, applied your check lines, and took your time. I do want to point out that at times you hatching got rushed and both ends of hatch lines don't make contact with the planes at times. This causes an undermining in the overall solidity of the form, so keep that in mind.

So congratulations, your box challenge is complete! This doesn't mean you're finished with boxes though. Keep practicing them in warm ups so you don't get rusty with them, and try to draw some larger ones too - on the scale of 1-2 per sheet of printer paper. Overall though, good work!