Starting with your cylinders around arbitrary minor axes, you've done a good job of consistently checking through your ellipses' alignments, and the ellipses themselves are generally drawn with a good deal of confidence, and maintain even shapes.

I am however seeing a pretty strong tendency not to vary your foreshortening all that much. You do go through a set from around 50-110 where you start applying a little more foreshortening, but there's definitely a lot to be desired, considering that in the homework section, I made a point of asking for a lot of variety in this regard (in bold).

Furthermore, a lot of your cylinders (especially towards the end) seem to show no shift in scale from one end to the other. With cylinders (and with all forms, but it's easiest to see this in cylinders) there are two different kinds of 'shift' when we compare one end to the other. The scale shift - where the end farther away from the viewer is smaller in scale overall than the closer end. That is, the basic tenet of perspective that was introduced back in Lesson 1: things get smaller as they move farther away. Then there's the 'degree' shift, where the width/degree of the farther end is wider proportionally than the end closer to the viewer. Both of these are aspects of foreshortening, so the viewer's subconscious will use them to gauge how much distance there is between the ends, and therefore how long a given cylinder is.

Looking at a number of yours - it's present in most of your cylinders on your last page, and throughout the set, but let's look at 145 in particular - you've got no scale shift which tells the viewer that there is no distance between the ends, and therefore the cylinder has a length of 0. Looking at the degree of the two ellipses, there is a notable shift, telling us there is some distance between them. That gives us a contradiction, and so the viewer can tell something's off, even if they can't put their finger on what.

Keep the shift on the two of them roughly consistent - it's not an exact science, but if there's some degree shift, there should be some scale shift as well. If there's a lot of one, there should be a lot of the other. But furthermore, based on the basic rules of perspective, there should at least be some foreshortening, this is not something you should be neglecting when laying out your cylinders.

Moving onto your cylinders in boxes, overall you're moving in the right direction here. When you started, you actually were making a similar mistake, keeping your lines roughly parallel on the page instead of trying to have them converge consistently (you were also extending them in the wrong direction too), but I'm glad to see that you rectified this rather quickly. From there, you made good headway and while there's still plenty of room for growth, you're working towards refining your ability to estimate the proportions that would allow a box you construct to be proportionally square on two opposite ends.

That is ultimately what this part of the challenge is about. By adding the ellipses to the ends, we can check whether their line extensions (the minor axis and contact point lines) converge consistently towards the box's own vanishing points. If they do, the ellipses represent circles in 3D space, and therefore the planes containing them represent squares. As you do your error checking, you adjust your approach to get a little closer in subsequent attempts, gradually refining your capacity for that kind of spatial estimation.

There is definitely a ways to go, but that's normal - keep working on getting those lines to converge more consistently, but I'm pleased with your progress and feel that what you've developed thus far will help you tackle the last couple of lessons in this course.

That said, before I do mark this challenge as complete, I want you to do a handful of revisions to show that you understand the issues with the first section, so I'll assign them below.