Oh well - these challenges were never designed to be fun. That's why the 50% rule exists! Although technically that wasn't designed to be fun either.... Drawabox isn't fun!

Anyways, the most difficult thing here is to learn to ignore your own self-judgment. The reason you submit for critique is because you aren't really going to be an effective judge - at least not yet - of your own progress. It's very easy to be self-critical, because we don't fully grasp what is expected of us. Our brains trick us into focusing on some things over others because we may feel that's what the exercise is about, but that isn't necessarily the case, or it may not be weighted in quite such a fashion. Even if we have the purpose of an exercise spelled out to us, we'll always be subject to this kind of misguided self-criticism. Instead, focusing on quieting one's mind and just executing the instructions to the best of your ability is always the focus.

Now, as I've basically implied already, you've done pretty well - despite your own misgivings. Ellipses are notoriously difficult, and I by no means expect students to have them mastered by the end of this course. Lines are far easier - but ellipses are a difficult beast to tame. That's why as you move forwads into lesson 6 and 7, I encourage the use of ellipse guides, so that you won't be further distracted by trying to execute perfect ellipses, and can instead focus on the core of each given lesson. Your ellipses will continue to improve as you practice the exercises that target them specifically in your warmups, but these lessons are best when not further complicated.

As a whole, I'm very pleased with your results. Throughout your cylinders around arbitrary minor axes, you've done a great job of constructing cylinders with a variety of orientations and rates of foreshortening, and you've been quite fastidious in checking for the "true" orientation of each ellipse. Even your ellipses are actually really well done, considering what I expect from students at this stage.

There is however one issue that I noticed here and there which I would like to clarify. The foreshortening of our forms is represented in two ways to the viewer. There's a shift in scale, caused by the convergence of the side edges, where the far end ellipse is smaller in overall scale than the end closer to the viewer. Then there's the shift in degree, where the far end is wider proportionally than the end closer to the viewer. Both of these help tell the viewer how much of the actual length of this 3D cylinder is "unseen" - that is, existing in the depth of the world which the drawing on the page cannot actually convey (unlike the part of its length that exists along the picture plane, running from side to side rather than towards or away from the viewer).

Now, if you look at an example like cylinder 119, you'll find that there's a pretty dramatic shift in overall scale, but not much of a shift in degree. This tells us that on one hand, there is a lot of foreshortening (and therefore the cylinder is actually much longer than what we see on the page), and that there is also very little foreshortening - that the cylinder is about as long as we see it drawn. That means there's a contradiction - two distinct and mutually exclusive signals being sent to the viewer.

Long story short, it's important to keep these two "shifts" consistent with one another. Either both can be extreme, or both can be minimal - but they have to match (or at least be generally similar).

Continuing onto your cylinders in boxes, overall you've done a good job here, but there is just one thing that's kind of holding you back. This exercise is focused around training students' instincts when it comes to constructing boxes that feature two opposite faces which are proportionally square. As far as this is concerned, I think your instincts have indeed developed quite nicely. By checking the line extensions of the ellipses' lines (minor axis, contact points) and comparing them to those of the box itself, you've been able to see how far off you were from having ellipses that represent circles in 3D space, and therefore planes that enclose them which represent squares in 3D space, you've been able to improve bit by bit as you moved through the set.

The only issue that got in your way was that you weren't extending your minor axes enough to feasibly compare them with everything else - so you ended up relying more on eyeballing that, which did help you progress, but I imagine it would have been more efficient to ensure that the minor axis was extended further. This is something you can keep in mind when practicing this exercise in the future.

All in all, you're doing quite well, and the further development of those instincts will serve you well throughout the next lessons. I'll go ahead and mark this challenge as complete.