Jumping right in with your cylinders around arbitrary minor axes, I'm very happy with your work here. Your linework is all confidently executed, resulting in evenly shaped ellipses and smooth, consistent straight edges for the sides. Additionally, while you did have some cases where for some reason you did not check your minor axis alignment (such as this page), you generally did a solid job of identifying them even finding fairly small discrepancies that could have easily been overlooked. This is particularly important, as we'll inevitably get into the territory where to the naked eye, our cylinders look fine, which can result in our improvement plateauing due to the identification of those areas of improvement becoming more difficult.

One point I did want to call out for you to keep in mind going forward is that when applying foreshortening to your cylinders, remember that it manifests both in the shift in scale from one end to the other (where in examples like 150, that far end is considerably smaller in its overall scale than the end closer to the viewer), as well as in the shift in degree, where the far end becomes wider than the closer one. The reason I'm mentioning this is that as both "shifts" signify the same thing - the amount of foreshortening being applied, which itself conveys just how much of the cylinder's own length exists there to be seen right on the page, and how much exists in the "unseen" dimension of depth - they do need to operate roughly in tandem, meaning a more dramatic shift in scale should be matched with a more dramatic shift in degree. In examples like 150, as well as others on that same page, we can see that the degree shift remains fairly consistent regardless of whether the foreshortening is intended to be shallow or dramatic. In cases of more dramatic foreshortening, this leads to a conflict, where the degree shift suggests that it's meant to be shallow, but the scale shift suggests that it's meant to be dramatic.

All that aside, overall you've still done a great job on this section of the challenge, so just keep that last point in mind.

Unfortunately, the cylinders in boxes do have a notable issue, but it's not what you likely expect given your submission comment. In fact, what you missed was precisely what addresses the concerns you were running into: you were not applying the line extensions as instructed in the video or written material.

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.

Looking at your work, it appears that you extended your boxes' edges, and marked in your minor axis lines (although these should have been extended fully back for each one, so that they could be compared more easily to the full set to which they belonged). What you were missing however were the two contact point lines for each ellipse.

Just as the box has 4 lines pointing towards each of its vanishing points, so too does each ellipse have one line meant to point towards each of the box's VPs. Of course the alignment of these will be off, but that's precisely what tells us where we need to adjust our approach to bring all of those line extensions together. In only checking a third out of the ellipse's line extensions, you were not getting a full picture of where that approach could be adjusted to yield better results (in regards to maintaining those squared proportions), and so the proportions could still be dramatically off without you realizing it.

Unfortunately that is going to require revisions, though I will not be assigning the full 100 (as I have for other students). Given the quality of your work otherwise, I'm only going to assign half that. Of course, that is still no small amount, but such heavy responses are merited - both to have the student reflect on what aspect of how they approached the material resulted in the lapse, as well as to ensure that you have cemented how to apply the approach correctly.