Jumping right in with your cylinders around arbitrary minor axes, you've done a great job. You've been extremely attentive to ensuring confident executions to both your straight lines and your ellipses, helping to avoid any signs of hesitation, wobbling, or unevenness. You've also been very fastidious in checking your minor axis alignments - you were very close to correct in most cases, but this did not stop you from catching some smaller deviations, which will ensure that you avoid plateauing as you keep closing that last little gap. Lastly, when it comes to varying your rates of foreshortening, and generally demonstrating a clear understanding of how both the shift in scale from one end to the other, and the shift in degree help convey a sense of how much of each form's length exists there on the page versus how much exists in the "unseen" dimension of depth, you're knocking it out of the park. It's very clear that you're comfortable rotating these forms freely, while maintaining a consistent idea of the specific form you're attempting to depict.

This carries over nicely into your cylinders in boxes, where you've done a similarly excellent job. 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 each ellipse such that it fit snugly within its containing plane, and applying the line extensions consistently and correctly throughout, you've armed yourself with ample information to help understand where your approach on the latest page has worked out well, and where it can be adjusted to continue bringing those convergences together. As such, I can see clearly that your judgment of those proportions has continued to sharpen and improve right up to the end of the set, and expect you'll be well equipped to move forwards.

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