Very nice work! Jumping right in with your cylinders around arbitrary minor axes, you're checking all of the boxes, so to speak. Your linework is clean and confidently executed, showing clear adherence to the principles of markmaking from Lesson 1, and I'm also pleased to see that you've been quite mindful and fastidious in checking your ellipses' alignments after the fact. I also noticed that - while this may have been something you picked up on more instinctually rather than consciously - you demonstrated an understanding of how the shift in scale between the ellipses on one end and the other, and the shift in degree between the same, work in tandem to create a consistent impression of how much foreshortening is being applied to a given cylinder - in other words, how much of that cylinder's length can be measured directly on the page, and how much exists in the unseen dimension of depth. The fact that you ramp up the shift in degree in proportion with how much smaller the far end is than the closer end suggests that even if this is something you were more consciously aware of, that your underlying spatial reasoning skills and general grasp of 3D space is indeed improving nicely.

Continuing onto your cylinders in boxes, your work here is similarly well done. Earlier on you did struggle a bit with having your ellipses fit snugly within their corresponding planes, but it's clear that your intent was correct, and your execution of that intent certainly improved over the set, in turn helping to make the exercise itself more effective.

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 those line extensions as fastidiously as you have here, you armed yourself with the information required to continually improve on your existing skillset, and that shows through the growth over the course of your homework here. I'm confident that this should prepare you well for what we explore in the next lesson, so I'll go ahead and mark this challenge as complete.