Hi I'll be handling the critique for your 250 box challenge, but first of all let me congratulate you upon completing it as it certainly requires time and patience.

-The first observation that I want to make is your use of the space on the page, you from time to time tend to draw small, keep in mind that this makes it harder for you to ghost through your lines and draw confident lines, also the accumulated error on the inner corner will be more noticeable.

-Now I want to address your linework, remember that when we add lineweight we want to do only on the lines that represent the silhouette of the page, never apply it on the internal lines, like the lines that represent your Y initial form.

-Another thing to keep in minn is that when you add lineweight you want to add just one superimposed line and ghost through it as much as you need to, this because we want to keep it subtle.

-It seems that as you progressed through the challenge your linework tended to be worse, maybe you ran out of patience as tou neared the end, so take rests and be consistent you want to get as much from this challenge as you can.

-A final note regarding your linework is that you should ghost through your hatching lines, remember that they are running on a flat surface and consequently should be as smooth as possible.

-You got better at aiming at the vanishing points so good job there, but keep an eye for lines converging in pairs as shown here.

The key things we want to remember from this exercise are that our lines should always converge as a set not in pairs, never diverge from the vanishing point and due to perspective they won't be completely parallel.

Overall while you did make a few mistakes your boxes are improving so far and with more mileage you'll continue to become more consistent. That being said I'll mark this lesson as complete.