Hi and congrats on completing the challenge. I'll be taking a look at your submission. I have to say that even from the first page your box constructions already look pretty good and I like the amount of work you are putting into checking your own mistakes. That said there's probably a few things I can help you think about. https://i.imgur.com/8PqQLE0.png Starting with this graphic one thing you always want to think about is that when you are drawing a box in perspective you always want to be considering the vanishing points otherwise you run into situations like box #81 where you have a box with lines DIVERGING from a vanishing point. This is one of the main things you want to avoid as it means the box is actually growing larger as it moves back into space. With all that said I'm not really seeing this problem is any other places and you did a great job extending all of your lines back correctly to check your work. I think you are at the point where you are able to get pretty consistent results with constructing boxes using the "Y" method and you probably need to up the difficulty in your constructions a bit. The boxes you will to have construct during the 250 cylinder challenge will be a nice step up in difficulty for you as you need to keep two planes square in perspective to put the cylinder faces in. Other than that I have to say your line quality was excellent throughtout the challenge. Great job using the ghosting method and your lines are extremely confident with a high degree of accuracy. Your attempts at hatching feel a tad rushed to me and I think treating them the same way you do every other line you draw would probably serve you a bit better. Ghost them and draw from shoulder with confidence. You also want to try and start and end the hatch marks at the edges of the plane instead of having them floating in the middle of the plane.

Overall, this was a really excellent submission with a lot of care put into it. I think you are at a place where your box constructions are very solid for the most part and any new progress you make is going to come pretty gradually at this point. I'm going to mark this as complete and good luck with lesson 2. Keep up the hard work.