Starting with your cylinders around arbtirary minor axes, you started out a little rough - in that you were primarily working with cylinders that appeared to have their vanishing points forced to infinity (resulting in no convergence of the side edges, and therefore no shift in scale from one ellipse to the other to convey foreshortening), but you did catch this within the first 30 or so and corrected it on your own. While the mistake was unfortunate, it's good to see that you identified the issue yourself and avoided it tainting the rest of the submission.

Aside from that however, you've done well. You've been extremely fastidious in checking the alignment of your ellipses after the fact. There were definitely more notable cases where the alignments were off early on, and this steadily improved over the course of the set. However, as you got more into the territory of "good enough", you were still careful to take your time in identifying the actual minor axis lines, even when they were only off by a little bit. This is good, as it will help you avoid plateauing in this area as you continue to practice.

Continuing onto your cylinders in boxes, your work here is solid, and you've definitely taken considerable effort to go through the instructions and apply them to the best of your ability. 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.

So, in applying the line extensions correctly and consistently checking them against one another, you're able to derive plenty of information and then act on it from one page to another, working to bring your convergences in and make them more consistent at every turn.

One thing to always keep an eye on is that as our cylinders get longer, we tend to be more prone to having the edges of a given set converge in pairs, with each pair being on opposite sides of the overall structure. We can see this in 246 for instance, with the blue lines - although the green lines that could be subject to the same issue converge more consistently. This shows me that you are working at it, and this was likely more of a stumble - but I wanted to call it out anyway just to be sure.

With that, I'll go ahead and mark this challenge as complete. Keep up the good work.