Hi Mermanomania, good job getting done with the 250 box challenge! I'm sure you will be quite relieved by the knowledge that you finally made it. I will give here my thoughts on some aspects of the challenge, pointing out where I think you did good and where you could eventually improve.

Convergence and 3D reasoning: You start the challenge I'd say with already a fair grasp of how box shapes rotate in 3D space, with some occasional imprecision. As one expects, your precision gets better and better further down the challenge and by the 100 mark your boxes are generally very believable as outlines of 3d objects, with some caveats that I will explain in the other section. The extension lines correctly extend away from the viewer all the time and generally show a quite precise convergence, or at least look convergent enough when the vanishing point is outside the page. In many of your boxes you handled very well the back corner, which is usually for most students the hardest part of the box if they draw the box from the front, so good job on that. Another good thing you did is that you have experimented with a wide variety of box shapes. The only thing in this section that I feel you could have tried to do more is playing with a wider range of foreshortening. While there's a few boxes with at least a set of sides with fair amount of foreshortening, most of your boxes tend to have moderately shallow foreshortening, meaning that perspective doesn't deform their apparent shape too much from their actual geometric shape. While in the instructions of the challenge it was recommended to draw more boxes with shallow foreshortening than not I think you could have pushed things a bit further in your experimentation with angles and make more boxes with radical foreshortening and try to experiment with different viewing angles, for instance by placing very close to the box 1 or 2 VPs.

Mark-making and confidence: You general mark-making is quite good. Your individual lines almost always lack wobbling. There's a bit of subtle arching in some of your first boxes, but going further down the challenge it begins to disappear quickly and by the end you lines look almost perfectly rectilinear. However, there are some problems with how your lines interact, making sometimes the whole a bit less than the sum of its parts, specifically when it comes to repeated lines and line-weight. Your boxes often show multiple repeated lines on what should be a simple, clear-cut edge of the box. Whether these lines were intended as added line-weight or not, the result subtracts from the illusion that we are trying to create, that we are looking at objects in space and not lines on a 2d surface, because even if the lines are individually confident the messiness of having multiple lines that are close but not completely overlapping makes it harder for our eyes to interpret the marks on the page as the bounds of an actual solid shape. For this reason, in drawabox we always try to work with the first mark we make, even if it is wrong: trying to correct these results often ends in messy situations that make the illusion of the drawing harder to sell. It's always confidence over accuracy in this course. The only time we should repeat a line is when we place line-weight, which is not a tool to correct a previous mistake but to make the shape feel more solid: it should always be limited to a single overlapping line. Also note that for this reason line-weight should only be placed on the silhouette of our boxes, so under no circumstance we should have repeated lines in the edges inside the outline of the box, as it is often the case with your homework. As a minor point, I feel that since your ability to make straight ghosted lines is quite developed by the end, you could start to focus a bit more on not overshooting your lines, which has also improved a bit during the challenge but could be improved even further. Another, final, minor point is that in the second half of the challenge your hatching lines become disconnected in the middle of the face, and also look a bit too much spaced in my opinion. Remember that hatching lines are lines just like any other, and as such they should be confident, smooth and continuous.

Keeping in mind all that I said, I think you handled well the major objectives of the challenge. In my opinion you're ready to move on to lesson 2 whenever you feel. Good luck and stay motivated!