Starting with your cylinders around arbitrary minor axes, I think you've done a pretty good job here and have shown a great deal of growth. Earlier on your ellipses were a little hesitant and uncertain, but as you push through the set, they become visibly more confident. In general, this confidence does result in your ellipses being a little more loose, but they also have a generally subtle, but positive impact on the entirety of your construction, including the side edges, so it's definitely a net positive.

I'm also pleased to see that you're pretty careful and attentive in identifying the correct minor axis line in red, even when the discrepancies were very slight. This attention to detail will help you avoid plateauing when the errors get too small.

I did want to call out ine quick issue however - in a few cases, such as cylinder 141 and 146, the rate at which the ellipses change from one end to the other becomes inconsistent. These changes - of which there are two, the change in the overall scale and the change in the degree of the ellipses - help convey to the viewer how much foreshortening is being applied to the form (and therefore how much of the cylinder's length exists in the 'unseen' dimension of depth). The thing is however, because they're signifying and conveying the same thing, they do have to remain reasonably consistent - you don't want a rapid convergence of the side edges resulting in a smaller ellipse on the other end, while also having that far end remain at roughly the same width/degree as the closer one. Or vice versa. The viewer won't know exactly what's wrong, but they'll be able to pick up on something being off.

Continuing onto your cylinders in boxes, I can similarly see a ton of improvement here throughout the set as well. 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 the line extensions correctly - especially to the ellipses' minor axes and contact point lines - you were able to continuously check in which direction you were progressing, and course-correct throughout the set. By the end, I can see pretty passably square proportions, which I think will serve you very well into the next lesson.

So! I'll go ahead and mark this challenge as complete.