Nicely done! I think what stands out the most throughout your work here is the comfort and confidence with which you approach drawing your ellipses. They're a little less certain early on, but you very quickly fall into a stride and start demonstrating considerable control over their positioning as well as the evenness of their shapes. It's also clear that you focus a great deal on identifying your ellipses' true minor axes after the fact, and this helps you gradually bring their alignments more in line with your intended minor axis as you progress through the first section of this challenge.

Another thing I noticed is that you demonstrate an intuitive understanding about how the shift in scale from the closer end to the far end, and the shift in degree actually relate to one another. This is something I leave for students to potentially figure out on their own, and while many seem to miss it here and there, you seem quite aware of it. That is, the fact that both of these shifts give the viewer a sense of whether the cylinder is longer or shorter. If the shift in scale or the shift in degree is more dramatic, then it suggests the far end is much further away (and therefore receives more foreshortening), making the cylinder longer.

The thing students tend to miss however is that this means you can't have a dramatic shift of scale, with the far end getting much smaller overall, but a minimal shift in degree where the far end remains roughly the same proportional width as the other. If one shifts dramatically, then so too should the other - and you adhere to this very confidently and purposefully in your work, to the point that it seems you're well aware of this fact. So, simply put: well done!

Continuing onto your cylinders in boxes, I am once again rather impressed. A lot of students, when drawing the longer boxes, tend to fall into the trap of having the sets of lines on one end of the box converge on their own, rather than converging to the same vanishing points as the opposite end. I suppose the closest example of this we can see is 95, where the blue and green lines do tend a little more towards converging early on either side. This is, however, an issue we don't really see very often in your boxes (aside from 95). 96, for instance, isn't that much shorter, and shows clear thought to which lines should be converging together, and maintains nice, consistent relationships.

As a whole, this exercise is largely about having students develop a more intuitive sense of drawing boxes that have a pair of opposite faces that are proportionally square. This functions similarly to how the basic line extensions of the box challenge allow us to gradually get better at aligning our lines to converge correctly. We identify where we were off, then we consciously change our approach a little here and there to improve the results. By adding the additional lines from the cylinder, we add the requirement that those opposite faces need to be square, simply because the contact points and minor axes will only align with the box's vanishing points if the ellipses represent actual circles in 3D space. If they do, then this means the planes containing them are square.

To put it simply, though this is the cylinder challenge, it all comes down more to teaching students about boxes once again. Who'da thunk it, that a course called drawabox would steer everything back to boxes? Anyway, you've demonstrated considerable adeptness on this front as with all the others, and your results are coming along great, and the ability to draw boxes with proportionally square faces will come in quite handy in the next lesson.

All in all I'm very pleased with your results, and this whole critique has basically been me pointing out the things you've done well. I'll go ahead and mark this challenge as complete.