Starting with your cylinders around arbitrary minor axes, the first thing I noticed was that through much of this, you approached the exercise with an element of roboticism. The same orientation of cylinders, running across the page, all in parallel, often with the same or similar rates of foreshortening (at least at first - you certainly did vary them plenty across the set, so that's good). This isn't inherently wrong, and I can certainly understand that because we're rotating our page for every mark (as part of the ghosting method) we're effectively drawing the same cylinder regardless of its orientation relative to its neighbours, it still seems rather against the spirit of the exercise. Compare this for example to your work in the 250 box challenge, which was dynamic and enthusiastic, and all we get here is just hum-drum monotony. It may not be incorrect, but it definitely has an impact on the mindset of the student doing the work. Keep that in mind for the future.

Stepping through the cylinders, you've done a good job of checking your minor axis alignments - you were quite thorough throughout the set. As I mentioned before, I'm also glad that you did explore different rates of foreshortening. Often I look out for a particular issue relating to the relationship between the shift in scale from one end of the cylinder to the other (the obvious matter of perspective where the far end is smaller), and the shift in degree (where the farther end is proportionally wider than the closer end). These of course don't just relate to cylinders - they relate to all forms, but the shift in degree is perhaps most easily portrayed here.

Those two shifts occur in tandem. As foreshortening increases, the shift in both also increases, resulting in a far end that is both proportionally wider while overall being smaller than the closer end. What I look out for are circumstances where one shift is more dramatic, but the other is shallower. I can see that cases like 139, 142, 119, etc. all show that when you push the scale shift to the extreme, you're also pushing the degree shift as well. That's good.

That said, towards the earlier cylinders, I did notice a tendency - for example, with 50, 68, 72, etc. when you maintained a similar scale shift (far end and closer end were about the same size), you were less consistent with your degree shift, sometimes making it widen far more dramatically than it should have. This is the sort of thing the viewer picks up on, noticing that something looks "off" even if they're not sure what.

In addition to this, do remember that even in cases where there's shallow foreshortening, that does mean there is still some. So avoid having the far end entirely equal in scale to the closer end.

Moving onto your cylinders in boxes, your work here is far more varied in terms of orientation and alignment, but also appears to focus primarily on keeping the foreshortening as shallow as possible. As mentioned just above, keeping all your sets of lines (which are parallel in 3D) parallel on the page as well is not a valid option. Vanishing points get pushed to infinity only in response to very specific alignments to the viewer. Aside from that, while foreshortening can be shallow, it always needs to be present, with you thinking about how each set of lines is meant to converge, even if gradually, towards a shared far-off vanishing point.

Now, there are plenty of cases where you're doing this correctly, maintaining shallow but present convergences between your lines. I just felt it was important to point out that there were a significant number where it appeared that you were purposely keeping those convergences at nil. Of course, there aren't many where you're exploring more dramatic foreshortening, so keep that in mind as well.

Aside from that, you're doing a great job checking those line extensions thoroughly, and using that information to assess how far off you are from the ellipses representing circles (since the closer the ellipses' line extensions are from converging towards the box's vanishing points, the closer they are to representing circles resting on the surface of the box). In turn that means those faces are closer to being square in 3D space, and as a whole this exercise has shown an improvement in your ability to estimate the correct proportions to maintain boxes with two opposite square faces. This will serve you quite well throughout the next lesson.

Keep the points I've raised here in mind, but I will go ahead and mark this challenge as complete.