Congratulations on completing the challenge!

Starting with your cylinders around arbitrary minor axes, I can see that you did start out a little uncertain, a little less confident, and a little prone not to drawing through your ellipses two full times. Fortunately you showed a great deal of improvement over the set in all of these areas - you transitioned towards drawing more with your whole arm, using more of the ghosting method (at least that's what the results suggest, I of course can't specifically know that for sure), executing your ellipses more confidently, and generally achieving smoother more even shapes throughout.

I'm also pleased to see that you put a good deal of variation in your cylinders' foreshortening, and as you did so, you demonstrated an understanding - whether subconscious or conscious - of the fact that the two main manifestations of foreshortening (the shift in scale from one end to the other and the shift in degree from one end to the other) must occur in tandem in order to give a consistent, cohesive sense to the viewer of whether what they see of the cylinder's length on the page is what exists (in the case of shallower foreshortening), or whether the bulk of that cylinder's length exists in the "unseen" dimension of depth (more dramatic foreshortening). If on the other hand we were to have a dramatic shift in the degree of an ellipse, but virtually no shift in scale, it'd suggest both simultaneously, leading to an inconsistency and a sense for the viewer that something is "off", even if they can't put their finger on what that might be.

And lastly, you've done a great job of identifying the discrepancies in your ellipses' alignment, going so far as to pick up on very small ones. This is important as it keeps you on your toes, and ensures that you keep improving and developing.

Continuing onto your cylinders in boxes, while this is understandably a very demanding task, it's one you appear to have handled 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.

Across this set, it's clear that you've put a great deal of effort into applying those line extensions correctly, and that you've paid attention to what they tell you, in order to improve and grow over the course of the challenge. Steadily throughout the convergences fall more consistently into line, and while there are outliers, the overall trend is one of definite growth and improvement. As a whole, I think your capacity to estimate those proportions regardless of the orientation of the form in space, is well developed, and should help you quite a bit into the next lesson.

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