Starting with your cylinders around arbitrary minor axes, you've handled this section fairly well. While earlier on in the set you did seem to stick to fairly shallow foreshortening (with some cases - 22, 23, 25. and 45 to name a few ending up with side edges that were too parallel on the page, which is explained as something to avoid here in these notes), you did shift to including more variation in the rates of foreshortening as you progressed through the set. Additionally, you've been mindful of executing your lines and ellipses with confidence, maintaining straight strokes and evenly shaped ellipses. I'm also pleased to see that you've been checking the alignment of your ellipses afterwards quite fastidiously. You weren't terribly prone to letting a "close enough" alignment count as correct - instead, you identified a lot of small discrepancies. This is good to see, as it'll help you avoid plateauing as you get more solidly into the range of your alignments being "good enough".

Continuing onto your cylinders in boxes, you've done quite well here too. You correctly identified that 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.

That said, I do want to remind you that it is best students not alter or impose any additional elements to the exercises, but rather that they focus only on what is laid out in the instructions - so in terms of you challenging yourself to draw cubes and not worry about which planes will receive the ellipses of your cylinder, you're making the exercise more complex before you've received feedback confirming that you were applying it correctly. This also means that you're taking your finite mental resources and spreading them across more than just the task that is assigned, which can very easily result in you missing the point of the exercise.

Fortunately that did not happen, and you've handled the exercise well - but I do want to reiterate that as mentioned back in Lesson 0 section that goes over how the course should be used, you should not alter any of the exercises while you have not yet received feedback confirming that you're applying them as intended. Once you've gotten that confirmation, you're welcome to alter the exercise as you wish. Prior to that point however, it's very easy for students to end up derailing their focus and needing to be assigned revisions which further demands time from both the student and the person giving them feedback.

Anyway, that aside you've done a great job here. I'll go ahead and mark this challenge as complete.