Jumping right into your cylinders around arbitrary minor axes, these are generally done decently, although there are two main issues that stood out to me:

• When it comes to the shift in degree from the end closer to the viewer than the other, this is something you definitely could stand to emphasize more, especially in cases where the far end is also considerably smaller. Generally these two "shifts" (in the overall scale and the degree from one ellipse to the other) operate in tandem, because they represent the same underlying concept: they tell us how much foreshortening is at work here, or in other words, how much of the cylinder's physical length can be measured directly on the flat page, and how much of it exists in the unseen dimension of depth. If the shift in scale suggests a lot of foreshortening is at play, then the degree shift would convey that as well. Admittedly you did improve on this front later into the set, with cases like 140 and 133 demonstrating this very well, but I wanted to call it out as this isn't something explicitly stated in the lesson material (I like giving students the opportunity to pick up on this naturally throughout the challenge - in the case that they do, it tends to stick better, and my explanation just nails it down).

• I did notice that often times when you don't quite draw through an ellipse two full times before lifting your pen, it also tends to be less confidently executed, resulting in a less even shape. We can see this in a lot of the far ends of your cylinders for the first hundred or so. After that, you've shifted to drawing through them two full times more consistently, so you essentially corrected the issue yourself - I just wanted to call it out to ensure that you're always mindful of whether or not you're drawing through your ellipses two full times, and what tends to occur when you aren't.

Aside from that, you're doing a good job. I'm pleased to see that you're checking the true alignment of your ellipses quite fastidiously, and that you're not only focusing on those discrepancies that are obvious. It's important to catch the more minor ones that could pass for correct at a glance, as that keeps us from plateauing in our growth, so you're on the right track there as well.

Continuing onto your cylinders in boxes, your work here is really well done. You've clearly put a lot of effort into adhering closely and consistently to the instructions. 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.

You've applied this methodology throughout the set, and it's clear that your capacity to judge those proportions in 3D space has indeed improved. There's always room to improve, and the intent here isn't to get you to a point of mastery with it - but I'm confident that what you've learned here will serve you well as you move onto the next lesson, where we get into a lot more geometric construction.

I'll go ahead and mark this challenge as complete.