Starting with your cylinders around arbitrary minor axes, my main concern here comes down to the linework itself. For the most part the cylinders themselves are fine, aside from a number of places where the relationship between the degrees of your ellipses is off. We can see this in cases like 111, 114, 118, 123, 144 among others - make sure you're always giving that farther ellipse a wider degree. How much wider would be determined by how much foreshortening is being applied, so if the far end is considerably smaller, make it considerably wider as well, whereas if the far end is only a little smaller in its overall scale, you'd only need to make it a little wider in proportion (so cases like 109 would also be incorrect, where you've got virtually no change in the overall scale of the ellipses, but the far end is much wider).

I'm assuming that this is a concept you do understand, given that it was still correct in the majority of cases, but given how many spots it was incorrect, you may want to review the ellipses section of Lesson 1.

Now the reason my bigger concern is your linework is that you don't appear to be applying the ghosting method, as you really should be for every freehanded mark throughout this course. The ghosting method forces students to separate the act of drawing a mark into distinct steps, each one devoted to a particular task. First we identify the specific mark we wish to make - in the case of straight lines, marking out the start and end point, but in general it's about identifying in specific terms what it is what this stroke needs to be, what job it needs to accomplish, and what angle would be most comfortable in terms of our approach. Second, we ghost through the motion itself, preparing ourselves by getting familiar with the motion that will be required. And finally in the third and last step, we execute the motion with a confident stroke, and without any hesitation, committing to what we've planned and prepared.

What happens when students don't make a conscious effort to apply the ghosting method to their freehanded lines, is that they'll gradually slip out of the habit of separating the steps out, and combine them into a single step, ultimately removing all of the benefit of breaking it up. In turn, this means that they're worrying about the specific nature of the stroke they wish to make while they execute it, which results in more hesitation, more wobbling, etc.

Long story short, use the ghosting method for every mark you freehand, and if you have not been practicing those basic linework exercises from Lesson 1 as part of your regular warmups, better late than never.

Continuing onto your cylinders in boxes, your work here is generally pretty solid. Your linework does improve (there certainly is room for continued improvement but the issues are considerably less noticeable here), and more importantly you've applied the instructions correctly. This exercise is really all about helping develop students' understanding of how to construct boxes which feature two opposite faces which are proportionally square, regardless of how the form is oriented in space. We do this not by memorizing every possible configuration, but rather by continuing to develop your subconscious understanding of space through repetition, and through analysis (by way of the line extensions).

Where the box challenge's line extensions helped to develop a stronger sense of how to achieve more consistent convergences in our lines, here we add three more lines for each ellipse: the minor axis, and the two contact point lines. In checking how far off these are from converging towards the box's own vanishing points, we can see how far off we were from having the ellipse represent a circle in 3D space, and in turn how far off we were from having the plane that encloses it from representing a square.

In applying them correctly, you've armed yourself with ample information, and I can see definite improvement in your estimation of those proportions over the course of the set, which aligns with the fairly clear signs that you're not just going through the motions of the line extensions, but rather are actively trying to apply what they tell you.

So! I do want you to take care in continuing to use the ghosting method for any freehanded linework, but as far as the challenge is concerned, you're heading in the right direction. I'll go ahead and mark it as complete.