Congrats on finishing the box challenge! You've improved a lot on it, but I'll try to point out what I see so you can keep improving.

A thing to keep in mind is that lines can not be paralell or diverge, they always have to converge. You have some instances where your lines diverge or are parallel, so when plotting your boxes, don't forget to check if they diverge or are parallel before commiting with the lines.

You also have a bit of fraying on both ends on some of your hatching lines. Don't forget to place your pen carefully at the start of each line so this doesn't happen.

Don't forget to also extend your lines as much as you can, don't worry if they collide with other boxes, it's very important to go all the way through with the extensions, as they'll show you your mistakes more clearly.

And here's another diagram that shows more orientations of boxes, so it gives you more ideas about what to try.

A good thing to think about is the relationship between lines. Thinking about them will help you get better convergences on your boxes, as explained on this diagram.