Starting off with your cylinders in boxes, your work here is very well done - both in terms of the mechanics of how these cylinders have been drawn, as well as with your linework, which is both confident and well controlled, showing a clear and consistent use of the principles behind the ghosting method (something a lot of students tend to loosen the reins on, to their detriment).

For the cylinders themselves, I'm pleased to see that you're mindful of the degree shift from one end to the other, that you're extremely fastidious in checking your minor axis alignments (catching both major and minor issues, ensuring that you're not likely to plateau as you get into that "good enough" territory), and that you appear to be aware (whether consciously or subconsciously) of the relationship between the degree shift and the shift in overall scale from one ellipse to the other. That is, the fact that they both represent the same thing, the foreshortening applied to the form, and thus work together to convey to the viewer just how much of this cylinder's length is visible right there on the page, and how much exists in the "unseen" dimension of depth. Given that they are manifestations of the same thing, we aren't going to see a shift in scale that is really extreme, with a very mild shift in degree - and that's something you've held to quite well throughout your work.

Carrying onto your cylinders in boxes, your work here is similarly 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.

You've applied your line extensions to great effect, and have obviously taken immense care in the planning, preparation, and ultimately execution of each mark. I can see clear signs that you've steadily reflected upon what the line extensions revealed, and gradually brought your convergences more and more in line. By the end, you demonstrate some very well refined instincts for proportion, so I expect this will help you quite a bit as you move forwards through the rest of the course.

So! I'll go ahead and mark this challenge as complete. Keep up the great work.