Congratulations on completing the 250 Box Challenge!

I have to say, throughout this entire challenge your boxes have been very well made. I can see that you really put time and effort into constructing your boxes. All of them are very clean looking with consistent, confident mark making. They look really good.

I can see that your boxes did improve over the course of the challenge. You still seem to struggle a bit with the convergence of the middle lines in your sets of parallel lines. If you look at this diagram here you can see how you should be thinking only of the lines that share a vanishing point and not the lines they share corners or with a plane. If you focus on those lines you can then examine the angles at which they leave the vanishing point. You will find that often, these middle lines have a very small angle between them and this angle will become negligible by the time they reach the box, which can make the lines themselves appear parallel.

I also noticed that most of your boxes have very distant vanishing points. This isn't a big deal in regards to the challenge. But I would suggest that when you do warm up boxes, that you try playing more with closer, more dramatic, vanishing points.

You did an excellent job adding line weight to your boxes. The additional weight blends really well with your original lines. Overall you did an excellent job on all of your boxes.