For future reference, best not to add those kinds of comments to your submission. While it's largely harmless, it would put me in a slightly awkward position if I felt that you needed revisions. As explained in this video from Lesson 0, unless you have very specific questions, it's best to just leave the submission comment section blank. I know you didn't need anything by it, so don't worry too much - just keep it in mind for the future.

Anyway, onto your work. Starting with your cylinders around arbitrary minor axes, you're generally doing okay, although I can see a couple issues I do want to call out.

• Firstly, I'm seeing a lot of doubled up lines. This suggests that while you may be applying the principles of markmaking and the ghosting method from Lesson 1 in part, you are allowing yourself to try to correct mistakes, or you're drawing marks automatically. You should not be. Each mark should employ the ghosting method (which I do see signs of), but that means that every stroke should be the result of planning and preparation, followed by a confident execution. If it's wrong, then it's wrong - but don't correct it, as this builds the impression in our minds that corrections are a valid course of action. This in turn can make us less likely to view the problem as being how we're thinking through it in the planning phase, which is where the real issue lies.

• Secondly, while further into the set you did include more cases of dramatic foreshortening, you did spend a good while either drawing most of your cylinders with shallow foreshortening - or, in some cases like 41 and 47 (just to name a couple), avoiding foreshortening altogether and instead drawing the side edges as though they were parallel on the page, rather than converging. If this was unintentional, then it's fine - sometimes we try to make our convergences very minimal, and we go a bit too far in that direction. But if it was intentional, then I want to give you a quick reminder that this is actually incorrect. This would only happen with edges governed by a vanishing point that is at infinity, which itself will only happen if that set of edges is oriented perpendicularly to the angle at which the viewer is looking out into the world (as opposed to slanting towards or away from the viewer through the depth of the scene). Because we're rotating our forms in this challenge randomly, there's no such opportunity to have such a perfect alignment, so there should be at least some convergence, even if it's only minimal.

That aside, you've done a good job of checking your minor axis alignments, catching both cases where they were off by quite a bit, as well as cases where the deviation was more minimal. While both are important, I'm very happy to see the latter because that's what helps us avoid plateauing as we get into that range of being "close enough" to fool the naked eye.

Continuing onto your cylinders in boxes, your work here is pretty solid. 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 your line extensions correctly, you basically gave yourself an idea of where you needed to adjust your approach (when drawing those planes on either end) to bring their convergences together more consistently, and in turn trained your brain to improve its instincts as far as maintaining those squared proportions go, regardless of how the form is oriented in space. And while there is certainly room for continued growth in this area, as there is for everyone (in the grand scheme of things 100 is not that many), you'll be able to continue honing those skills in your warmups. For our purposes as we move into Lesson 6 however, you should be in a good position.

One thing to keep in mind though, is that when you're drawing those ellipses, it is quite important that you get them to fit as snugly in their enclosing plane as possible. Additionally, make sure you're always keeping a close eye on the ellipses' alignments when drawing your minor axes - sometimes you might think you're pretty close, but you might be farther off than you think. For example, here in number 63. As a result of that mistake, while the farther plane was narrower than it should be, you didn't catch that issue, and so wouldn't know to correct it in later attempts.

Anyway, all in all, pretty solid work. Just keep what I've said here in mind as you move forwards, and apply it in your warmups. I'll go ahead and mark this challenge as complete.