Starting with your cylinders around arbitrary minor axes, there are a number of things you're doing fairly well here:

• Your side edges are executed cleanly, using the ghosting method to achieve confident strokes with a fair bit of accuracy.

• You're fairly fastidious in checking the alignment of your ellipses in red.

Additionally, you were executing your ellipses quite well early on - doing so confidently, keeping the ellipses evenly shaped, etc. - but this did take something of a turn for the worse starting with this page. Your execution became more hesitant and wobbly, suggesting perhaps a less consistent use of the ghosting method, and perhaps an inclination away from using your whole arm from the shoulder. It appears that this was after a pretty significant break, and it did improve again after several pages of struggling.

I can only assume that in these gaps, you're probably not keeping up with your warmups. These warmups, we're meant to be doing for 10-15 minutes every day, or every few days, or at least with some regularity, are where we continue to practice the exercises we've been introduced to throughout the course (picking 2 or 3 different ones each time) so we can continue to sharpen our skills and avoid having them get rusty. While ellipses may seem simple, they're really not (to the point that for Lessons 6 and 7, we allow and encourage students to use ellipse guides to avoid being distracted from the core of those specific lessons). Even those students who stick faithfully to their warmups, following all of the instructions for the course, are expected to still have difficulty with them (to the point of us choosing to eliminate that problem from those later lessons).

Continuing on, it appears you may have missed an important instruction for this part of the challenge. I can understand how that might happen if one is spreading the work across a long and somewhat inconsistent period of many months, and it certainly emphasizes the importance of going back over the instructions after every break (or even skimming them at the beginning of each sitting) to ensure that you are doing what was asked.

In the assignment section for the challenge, which you'll find screenshotted here, students are asked (in bold) to vary the rate of foreshortening across their cylinders throughout the set. That is something you did not do.

What you do appear to have done instead, is to artificially eliminate foreshortening from all of these cylinders, forcing those side edges to run roughly parallel to one another on the page, and placing their shared vanishing point at infinity. This concept of vanishing points at infinity was discussed back in Lesson 1. It is essentially what happens when we have 1 or 2 point perspective - we still have 3 vanishing points, but some of those exist at "infinity", so the lines they govern, despite "converging" towards this point that is infinitely far away, never actually get any closer or farther away from one another.

This, unfortunately, is not something we control. What we do control is the orientation of the cylinders, and it's that orientation that determines where the vanishing point will be. More specifically, a vanishing point will only ever "go to infinity" in the specific case that the lines they govern run perpendicular to the viewer's angle of sight, not slanting towards or away from the viewer at all. Given that this challenge has us drawing cylinders that, similarly to the boxes in the box challenge, are freely rotated, we can pretty much assume that the alignment would never be so perfect as to result in a vanishing point at infinity.

Furthermore, were we to look at actual boxes (like the boxes in the other section of this challenge), even if we did align a box so perfectly that two of its vanishing points were to sit at infinity, that would place the third vanishing point squarely on the page, with its lines converging quite dramatically and rapidly towards it. In perspective projection, we cannot have all three vanishing points of a rectilinear box at infinity. This is something we see in orthographic/axonometric/isometric projection, but those are distinctly separate from "perspective projection", which is an approach for representing 3D space on a flat surface in a way that replicates human binocular vision. Those other approaches, rather than putting all vanishing points at infinity, simply do not have actual vanishing points at all.

Now, it does seem that for a while in your cylinders in boxes (up to about halfway through) you did just that, putting all your vanishing points at infinity and artificially trying to keep everything parallel on the page. After that point, it was somewhat mixed - you were definitely converging some sets of lines towards concrete vanishing points, but there was often at least one set that would still attempt to stay parallel on the page.

Another point that stood out to me quite a bit is that you don't appear to have been checking your ellipses' minor axes correctly here. I grabbed a couple of pages in the middle of your set and identified the true minor axis on it. As you can see there, on each page, only one ellipse's minor axis was fairly close to the line you'd marked out for it - all of the others were wildly off.

The issue here is not the fact that your ellipse was misaligned. That's expected. The issue is that in not identifying the cases where that minor axis was off, you left yourself with no way of knowing what you were doing was incorrect, and thus no way of adjusting your approach. This analysis - like the line extension analysis from the box challenge - speaks to the core purpose of this part of the challenge, and so when we do it incorrectly, we undermine the effectiveness of the exercise.

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.

Unfortunately, this means that with the actual minor axis being incorrectly identified, as well as the earlier issue of all of your lines being parallel on the page, you weren't able to apply the exercise towards its intended purpose.

Now, in such a situation, I would normally ask the student to do a full redo of the challenge, from start to finish, and in your case that is certainly warranted. I have had at least a few students who've stumbled into similar mistakes, and while they were by no means happy to have to redo the challenge as a whole, they did complete the task. Not only did they complete it, but they did so with such keen attention to every single mark they put down, and every single instruction. Not just in this challenge, but in the lessons that followed.

In your case, however, I am not going to assign a full redo. Instead, I will ask for half. That in itself is no easy task, nor should it be - reading and following the instructions is critical towards ensuring that your time (and my own) is not wasted. You'll be able to submit these revisions as a reply to this critique, without spending any additional critiques - but do be sure to give yourself the time to go through the instructions as carefully as you can. And of course, do not forget to do your warmups.