Starting with your cylinders around arbitrary minor axes, when it comes to the cylinders themselves, you're doing fairly well - you're checking your minor axes fastidiously and identifying both major and minor discrepancies so you avoid plateauing as the alignments get into that "close enough" zone. When it comes to the underlying principles of markmaking however, and how you're actually making the individual ellipses and side edges, I can see that you aren't as attentively employing the ghosting method (resulting in marks that are a little wobbly at times, or otherwise not entirely straight in the case of lines, or smooth/evenly shaped in the case of ellipses). Additionally, I can see that you are not consistently drawing through your ellipses two full times - you're definitely aware of this requirement, as you are drawing around the elliptical shape more than just once, but you tend to stop short which suggests that you're not entirely attentive to specifically how you're approaching it.

In essence, you definitely have a lot of room to give each cylinder, and each individual mark, more time, in exchange for stronger results. Remember - as discussed back in Lesson 0, your responsibility is to give yourself as much time as you require to execute the work to the best of your current ability. Applying the ghosting method to each and every mark is of course tedious, and could result in the work taking far longer, but it is by pushing yourself to the limit of what you can do right now that you will be able to push yourself forward. It also plays an important role in ensuring that the feedback you receive is able to focus not on the issues that come about due to you simply not giving it as much time as you could have, but the actual issues of misunderstanding. The former have a tendency to obfuscate the latter, making the work harder to critique, and ultimately meaning that you get less out of it.

As it stands, I'm not worried enough to assign revisions on this front, but I will say that you can certainly be doing a lot more to benefit from this kind of exercise - so when you do it as part of your warmups, you need to take more care not to rush, and instead focus on what you can do to make each individual mark to the best of what you can right now.

Continuing onto your cylinders in boxes, your work here is generally well done. Your lines are visibly more confidently executed, and while investing a bit more time into the ghosting method's planning and preparation phases will still help, I do feel that you approached your linework here with more care than the previous section. Additionally, the nature of this exercise puts a lot of emphasis on the line extensions, and you've handled those well.

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 checking y our line extensions correctly, and being attentive to them especially when they're way off (for example, cases like 204 and 205, where the boxes were definitely more rectangular), you've given yourself plenty of information on which to assess how to adjust your approach to help improve the proportions in your results. It's across this section of the challenge where I see the most obvious and visible improvement, and I think it actually cycles back into encouraging you to put more time into those individual marks. As a whole, I think that you're well equipped to move onto the next lesson, and that while there's always further room for improvement and growth, your current ability to estimate those squared proportions will serve you well as you move forwards.

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