While you made some progress with constructing your boxes throughout the challenge there are a few fundamental areas that you did not do correctly which slowed your growth. I suspect that you may have been overly enthusiastic about getting into the challenge, and did not read the instructions thoroughly enough. This led to a number of mistakes that could have been more easily avoided.

The most immediate issue I noticed is that you did not extend your lines correctly. You only extended two lines per set instead of all four, making the line extensions ineffective. If you reread this section of the instructions you can see how you are meant to extend your lines and why.

When I look closer at the boxes themselves it is unclear whether or not you were thinking about how the lines are actually supposed to converge as they move away from the viewer. If you look at this diagram you can see how the sets of lines do not remain parallel on the page but instead begin to converge towards their shared vanishing point as they move away from the viewer. This is something you should be thinking about while constructing your boxes. The diagram also shows that when you think of your sets of lines and the angles from which they leave the vanishing points, usually the middle lines have a much smaller angle between them, and this angle will become negligible by the time they reach the box. This can serve as a useful hint.

With this in mind I will be assigning you an additional 100 boxes. I strongly encourage you to do these 100 boxes on the recommended printer paper at 8.5"x11". The sketch book you are using appears small and more importantly the paper you are using is not ideal for working with Drawabox and the pens we use. Paper with a toothier texture can shorten the lifespan of your pens and the smaller size will make it needlessly difficult to draw from the shoulder. You will also want to push yourself to draw your boxes bigger as drawing bigger will help you engage your brain's spatial reasoning skills, whereas drawing smaller will impede them.

As you construct your 100 boxes you should frequently refer to the instructions to ensure that you are doing your revisions correctly.