Jumping right in with your cylinders around arbitrary minor axes, great work. You've clearly put effort into varying the rates of foreshortening throughout the set, and have executed your marks with confidence and care, achieving smooth, (usually) straight lines, and evenly shaped ellipses. I can also see that you've been quite fastidious in checking the alignment of your ellipses, catching not only the more obvious discrepancies but also those more minor ones which can be easier to miss. This is important, because it shows that you're well equipped to continue making full use of this exercise without plateauing, even as you get into that "close enough" territory.

Another observation worth mentioning is that I can see a clear correlation between the degree shift from one ellipse to the other, and the shift in overall scale. This is something I leave for students to pick up on themselves, as those things we identify on our own (whether consciously or subconsciously) tend to take root more deeply, but basically since both of these "shifts" represent the same thing - how much foreshortening is being applied, and therefore how much of the cylinder's length can be measured directly on the page, versus how much exists in the "unseen" dimension of depth. And so, it does matter that the degree of the far end get considerably wider as the overall scale shrinks more dramatically, since this would allow both visual cues to agree that more of the cylinder's length exists in a way that cannot be directly measured in two dimensions. So, good work there - and if you weren't fully conscious of that relationship (despite applying it subconsciously), you are now!

Continuing 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.

In applying these line extensions correctly and carefully throughout the set, you've been arming yourself with ample information to better understand how to adjust the proportions of your boxes. While there is always going to be more room for improvement on this front, I can see that your estimation of those proportions is coming along quite well, and that you should be well equipped to face the challenges Lesson 6 poses in this regard.

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