Starting with your cylinders around arbitrary minor axes, first let's start with the good. The core cylinder-related principles have largely been executed well, with a good deal of variation in your rates of foreshortening, you're mindfully checking your minor axis alignments, and you're largely keeping the two manifestations of foreshortening (the shift in degree, and the shift in scale, of our ellipses from one end to the other) consistent with one another to clearly communicate a single answer to the question of "how much of this form's length is visible right there on the page, and how much exists in the unseen dimension of depth?"

Where I think your work is lacking comes largely to the concepts introduced in Lesson 1 - that is, markmaking. It seems here that you may have allowed yourself to slip off the wagon, so to speak, when it comes to applying the ghosting method to every mark we freehand throughout this course. This isn't at all uncommon, but it tends to result in students spending less and less time in the planning and preparation phases (where we identify the nature of the mark we wish to make and arm ourselves with all we need to execute it) - that's where all the time is meant to be allocated - and then they compensate by spending more time in the execution phase to try and think through those things as they draw. This of course results in more hesitation, leading to lines that are slightly wobbly and ellipses that aren't entirely even.

When it comes to your ellipses, I feel you improve on this somewhat as you push through the set, but it is important that you more mindfully apply the ghosting method as laid out here in Lesson 1 as you work through the rest of the course.

Continuing onto your cylinders in boxes, your work here is quite well done. 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 throughout the work, you've armed yourself with lots of information on how the results could be improved in the next, and you clearly applied that going forward, slowly bringing those proportions in line more and more. While this intent is not obvious throughout the lesson, this is a time where I feel not spoiling the surprise has its benefits. It's easier to trick someone into developing their instincts, as the student's own thoughts don't get in the way. As it stands, there's certainly lots of room for continued growth on this front, as there always is, but you should be well equipped to tackle the kinds of constructions we'll be dealing with next.

Anyway, solid work overall, but be sure to pay attention to that freehand markmaking. I'll go ahead and mark this challenge as complete.