Starting with your cylinders around arbitrary minor axes, you've done quite well. I was initially a little spooked by the fact that your first page seems to neglect any and all convergences whatsoever - as though you're forcing your vanishing point to infinity, in the manner discussed in Lesson 1. It's worth discussing why that would be incorrect, and why it's a very good thing you didn't continue holding to that path later on.

In essence, we do not control where the vanishing point goes. Rather, we control how the form itself, and thus edges of which it is composed, are oriented in space, and it is that in turn which determines where the vanishing points go. The vanishing point will only go to infinity if the set of lines it governs run perpendicular to the viewer's angle of sight - so basically running straight across their field of view, not slanting towards or away from them through the depth of the scene. This of course is not the orientation of most, or really any of your cylinders - and thus, having the side edges running parallel on the page as they did in that first page would be a significant mistake. Taking that one step further, since we're rotating our cylinders freely throughout this challenge, the chances of our cylinders aligning so perfectly as to ever be drawn with a vanishing point at infinity is so slim that we may as well ignore it, and always draw our cylinders with some convergence, even if only a little. The same would of course go for the boxes later in this challenge, as well as those from the box challenge.

Continuing on though, you largely knocked it out of the park. Your ellipses are confident, you've got plenty of variation in your rates of foreshortening. You're also fastidious in checking the alignment of your ellipses. There's just one other thing I want to call to your attention, and it has to do with the relationship between the two major manifestations of foreshortening.

There's the shift in scale, where those converging side edges cause the farther ellipse to be smaller overall, and there's the shift in degree - where the far end becomes wider. Because these are both manifestations of the same thing - the foreshortening, the sign of how much of that form's length is visible plainly on the page, and how much exists in the "unseen" dimension of depth - it becomes necessary for them to effectively operate in tandem. Meaning, we shouldn't end up with situations where the far end is noticeably smaller, but the degree remains relatively consistent. Can see cases like this here and there throughout your work - for example, number 67 and 64.

That said, as you progress through the set, it does seem like you pick up on this yourself, and it comes up less often, and less obviously.

Continuing onto the cylinders in boxes, you've done a great 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 the line extensions consistently throughout, and keeping an eye on how you can adjust your approach for the next time to bring the convergences together, you've clearly shown signs of improving your judgment for those proportions.

One thing I should point out however is number 71 on this page. Here you ended up with a very skinny cylinder, which is fairly obviously incorrect in terms of the proportions of the box - but it's not as obvious because the minor axis is so far off that it actually ends up coinciding more with the green line extensions (which are meant to be one of the contact point lines). These kinds of mistakes can be tricky if we don't know to look out for them. We can see a similar issue with 95.

But, all in all, you've made solid progress, and by and large your improved sense of proportions should serve you well into the next lesson. I'll go ahead and mark this challenge as complete.