Starting with your cylinders around arbitrary minor axes, it's clear that your comfort level with constructing these forms improved quite a bit throughout the set. Towards the beginning they were definitely haphazard in a number of ways - the ellipses were often loose, the edges didn't necessarily touch the ends in the right places, and the accuracy of your ellipses' placement did appear to be an area of struggle. As you got past the 100 mark, there was definitely a visible improvement - your ellipses were tighter and more confident (although not without more room for improvement), and your execution of those side edges was far more accurate and consistent. The alignment was getting better too.

Another thing that stood out was that by the end, you're maintaining a pretty solid grasp of how to consistently demonstrate proper foreshortening. That is, the fact that foreshortening manifests as both the shift in scale from one end of the cylinder to the other (closer end is bigger, farther end is smaller) as well as the shift in degree (closer end is narrower, farther end is wider). One issue I look out for is where students will apply those shifts independently of one another - adding a more dramatic scale shift and a more minimal degree shift, or vice versa. In your case however, you appear to be keeping them consistent for the most part, avoiding those kinds of contradictions where one thing suggests a lot of foreshortening, and another suggests very little. So nice work on that front.

Continuing onto your cylinders in boxes, your work here is coming along nicely as well. You've diligently applied those line extensions, and in doing so, you've been developing your ability to construct boxes that specifically feature opposite faces which are proportionally square. Ultimately that's what this exercise is about - by throwing the cylinder's two ellipses in there, and checking whether their line extensions align to the box's own vanishing points, we can check if the ellipses represent circles in 3D space. If they do, then the plane enclosing them must therefore represent squares in 3D space. With every new page, you were making adjustments to bring those alignments closer, and while there's still plenty of room for improvement, I think you've made considerable headway, and the intuition you've developed here will serve you nicely throughout the next lesson.

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