Starting with your cylinders around arbitrary minor axes, you've a pretty good job. You've been mindful of including lots of variety to the rates of foreshortening, and you've been quite fastidious and thorough in checking the alignment of your ellipses - often finding even small deviations that are precisely what we need to be attentive to, in order to avoid plateauing as we get into the territory of being "close enough".

I did notice some little discrepancies in some of your linework though - cases of sloppiness that suggest that you're not necessarily giving yourself as much time as you need to apply the ghosting method in all of its stages, as thoroughly as you should be. I certainly understand that being 100 cylinders into a set of 150 can be exhausting, which in turn can lead us to take shortcuts or reducing the time we invest in things like the planning and preparation phases of the ghosting method - but every action we take is the result of our own choices and decisions. It's critical that even in situations like this, we either make the choice of applying the steps as we know them, or simply taking a break in order to recharge. As we get further into the set, I can see more instances of your side edges arcing, as well as gaps where those side edges should be touching the ellipses on either end at their apex.

Another point I did want to mention is that ideally, we want the two shifts that represent the foreshortening of our forms - that is, the shift of the scale from one ellipse to the other (where the far end gets smaller overall) and the shift in degree (where the far end gets proportionally wider), to occur at roughly the same rate. This isn't strictly something you missed - I don't mention it in the material as this is something students will sometimes pick up on themselves, which helps that concept stick a bit better than if I simply explained it wholesale - but I always make sure to explain it in order to solidify the concept.

In effect, since both of these shifts represent foreshortening, they are the signs the viewer will use to judge just how much of the cylinder's length exists right there on the page, and how much exists in the "unseen" dimension of depth. As they represent the same thing however, it also means that they must operate in tandem - a more dramatic shift in scale due to greater convergence of those side edges should be met with a similarly dramatic shift in degree. Situations where they do not operate together - for an example, you can look at 139 - will stand out as being "off" to the viewer, even if they're not entirely sure as to why.

Continuing onto your cylinders in boxes, I'm noticing a couple things of note. 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.

As a result, how we apply the line extensions is pretty significant to the heart of this exercise, and I'm noticing some definite deviations - although to varying degrees - to how closely you apply this. For example, you appear to be rather inconsistent in which line extensions you apply - there are quite a few cases where you'll apply some of them, but not others. For example, on each cylinder on this page, you're extending your minor axes (in red), as well as one set of contact point lines (in blue), but not the other (which you usually do in green). Fortunately this is not the majority, but there are other pockets where you simply don't extend all your lines.

Another concern is that you appear to extend your lines, in many cases, a fairly short distance - and you do so in both directions. Meaning, you extend them away from the viewer (correctly) and towards the viewer. Extending them towards the viewer isn't of any real benefit to us, but it isn't inherently harmful. Limiting how much we extend away from the viewer however can undermine the effectiveness of this kind of analysis, to a point however.

Now, aside from that, your linework is in many cases pretty sloppy. I can see clearly that you're not giving each and every mark as much time as they require of you in order to fulfill the student's singular responsibility in this course. That is, to be drawn to the best of your current ability. I certainly understand that the exercises are boring, and that they can wear on your patience - but I think you may want to review this video from Lesson 0.

I'm going to assign some minimal revisions below. I don't think any of the specific mistakes are big deals, but I am concerned about the erosion of your patience, and would like to see that addressed before we move forwards.