As a whole you've done a solid job here across the two sections of the challenge, with my only real complaint being that not numbering the cylinders, or at the very least the pages, does make it a lot harder to know what order in which they were done, and whether they were all completed. Keep that in mind in the future, although being that it's the last mandatory challenge that has you doing quite so many, I suppose it's not an issue that'll come up for us again.

Starting with your cylinders around arbitrary minor axes, your linework is excellent. Your side edges are smooth and straight, and your ellipses are evenly shaped - all of which suggests that you're executing your marks with a lot of confidence, and applying the general principles of the ghosting method. You're also demonstrating a good grasp of how foreshortening alters the different aspects of the cylinder's form - especially when it comes to having the two manifestations of foreshortening (the shift in degree and the shift in scale from one ellipse to the other) work together to represent a consistent idea of how much foreshortening is being applied. Foreshortening itself is after all a way to convey depth to the viewer, and establish just how much of the length of that form is visible right there on the page, and how much exists in the "unseen" dimension of depth. If there are multiple signs that work to convey to us how much foreshortening is applied, we must of course have them give a consistent message, and avoid situations where one suggests there's a lot of foreshortening, and another suggests that there's very little - like having a more dramatic shift in scale, but no shift in degree to match. As a whole you've demonstrated a very good grasp of this, though I feel explaining it as I have done can be valuable as many students pick up on these principles more intuitively throughout the challenge, and may not fully grasp the why's of it all.

Carrying onto the cylinders in boxes, you've similarly done a very good job here. 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 consistently throughout, you were able to identify where your approach could be adjusted to tighten up those convergences, and in so doing, you gradually honed your brain's grasp of 3D proportion. While there is certainly more room for improvement and growth (as there always is), I do feel that your progress here should be advantageous for you as you move onto the next lesson.

So! I'll go ahead and mark this lesson as complete. Keep up the great work.