Thanks for your patience in waiting through the promptathon. Now that it's over, let's dive into your critique.

Starting with your cylinders around arbitrary minor axes, your work here is a little mixed - there are a lot of cylinders that are drawn well, but scattered throughout the set there are also a lot of weird ones that suggest a misunderstanding of which end of the cylinder is which (in terms of which is closest to the viewer, and which is farthest away).

There's basically three tools we use to convey whether an end of the cylinder is closer to the viewer, rather than farther away. There's the hatching lines (which we always place on the end facing the viewer), and then there's the shift in scale and the shift in degree (the end with the larger overall scale is closer to the viewer, and the end with the narrower degree is closer to the viewer). In truth it's really just the two tools, with the hatching letting us reinforce what the other two should agree upon.

Looking at this page, we can see very clearly that on 148, the ellipse on the left side represents the end closest to the viewer, because it's the narrower of the two (so it has the narrowest degree), and because its widest span is still wider than the widest span of the far end, so its overall scale is larger. As such, you chose that ellipse to fill with hatching, reinforcing the fact that it is the one closest to the viewer.

If we look instead at 149 however, we have the ellipse on the left side which is wider (therefore the farther end), but its overall scale is also larger (therefore it's the closer end). And if we look at the ellipse on the right side, it is of a narrower degree (so closer to the viewer), but smaller in its overall scale (therefore farther away from the viewer). You chose to fill in the ellipse to the right side with hatching, but in truth neither checks the boxes.

149, as well as 150, 146 and 147 on that same page are incorrect, because they do not agree upon which of their two ends is closer and which is farther. As a result, they look off to the viewer - although they won't necessarily be able to tell you why.

As to why these issues came up in your work (and they are present throughout the set, and actually do become more frequent after the 100 mark), I can't specifically say - but it's going to come down to a mixture of, you got careless and forgot to think about the logic/reasoning behind the steps we follow when constructing our cylinders (so you didn't notice when those instructions were jumbled up), and your grasp of that logic may not be as solid just yet. That is definitely something you'll want to review from the instructions, and we will need some revisions to ensure that you are understanding the concepts correctly.

Aside from those inconsistencies, the core mechanics of your linework is all looking good - your lines are confident, your ellipses are smooth and evenly shaped, and you were quite fastidious in checking the alignment of your ellipses. Honestly the source of the inconsistency could simply be that you hyperfocused on one aspect of the exercise (the alignments) and forgot about the other considerations.

Continuing onto your cylinders in boxes, your work here is more consistent in its following of the instructions, and is by and large well done. 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 those steps correctly, you ensured that your analysis of each page of boxes/cylinders armed you with useful information that could be applied going forward, and as a result your grasp of these proportions and how the choices you made in drawing on the flat page would impact what was represented in 3D space certainly improved and developed over the set.

Before I mark this challenge as complete, I will need you to do an additional 30 cylinders around arbitrary minor axes. Do be sure to review the instructions for that section beforehand - also, reviewing Lesson 1's ellipses material may be a good idea as well. Lastly, take your time and make sure that every choice you make is a conscious one. The issues you ran into in your first attempt at this section are avoidable, as long as we take our time and think through each choice we make, so I will be expecting for this issue to be addressed in its entirety (or very close to it).