One significant issue that stands out right off the bat is that you appear to have drawn both your cylinders from the first section, and your boxes from the second, with absolutely no foreshortening whatsoever. This presents two key problems:

Firstly, for the homework assignment listed in the first section, I specifically stated (in bold) that you should be varying the rate of foreshortening for your cylinders, including some with shallow foreshortening (with gradual convergence) and others with more dramatic foreshortening (more rapid convergence), as shown here. You obviously did read it, but perhaps by the time you started working on the exercise, you'd forgotten.

Secondly, what you drew throughout the challenge was neither shallow nor dramatic foreshortening - it was a complete absence of foreshortening. This issue was also present in your work for the 250 box challenge, and was specifically called out in the critique you received.

In Lesson 1, we talk about the concept of vanishing points being pushed "to infinity", causing the lines drawn on the page to be parallel, as you've drawn them here. This happens only when the form in question is aligned specifically to be perpendicular to the viewer's angle of sight. It isn't something we can choose to assert over our drawing - it only happens in specific cases, and because we're rotating these cylinders freely, we can basically guarantee that it will never happen in these kinds of exercises. Therefore there should always be at least some foreshortening.

Foreshortening is one of the visual cues the viewer uses to identify roughly how long a form is. Think can think of it as a multiplier - there may be a small distance between the two ends of a cylinder as it's drawn on the page, but if there's really dramatic foreshortening applied to that cylinder, then the viewer knows that it is in fact much longer. If there is very shallow, gradual foreshortening, then they'll know that it's quite short. And if there's no foreshortening at all, it's like multiplying the cylinder's length by 0 - it tells the viewer there is absolutely no distance between those ends, and therefore despite the fact that they can see that the cylinder has at least some length on the page, the complete absence of foreshortening tells them that it has no length at all, that there is no distance or space between those ends. This results in a visual contradiction, and the viewer will know - even if they can't specifically pinpoint why - that something is off.

Along with this, there is also another contradiction. Foreshortening manifests in two ways - the shift in scale, where the far end is smaller than the closer end (which is what your cylinders are missing), as well as the shift in degree where the far end is wider than the closer end (which you did include in your drawing). The presence of a shift in degree suggests to the viewer that there is some foreshortening, but the lack of shift in scale suggests that there is not. Again, the different parts of the drawing do not agree with one another, and so the viewer assumes they are just looking at a drawing on a piece of paper, not a solid, three dimensional form.

Moving onto your cylinders in boxes, and setting aside the foreshortening issue for a moment, you're doing a good job of applying the error checking/line extensions here, although I think you might not be taking what those line extensions are telling you into consideration while drawing your next set of boxes.

The goal with this exercise is essentially to help you develop your intuition when it comes to constructing boxes that feature two opposite faces which are proportionally square. The cylinders themselves - or rather, the ellipses on either end - add onto the normal box challenge line extensions. If the ellipse's lines (the minor axis and contact lines) converge towards the same vanishing points as the box's edges, then the ellipse represents a circle in 3D space. If that ellipse represents a circle, then the plane enclosing it represents a square in 3D space as well.

In order to improve on this front however, you have to actively be taking into consideration what those line extensions are telling you, and alter how you draw the boxes to try to get the extensions to line up better. You have to consciously make those tweaks with every page - and I don't entirely get the impression that you are doing so here. Most notably, your minor axis alignments tend to be off quite a bit, which suggests that you need to be making those boxes wider or narrower in a given dimension, rather than drawing them the same way each time.

Now of course, the foreshortening is still a major concern, and you haven't applied the feedback you received back in the box challenge. As a whole, you could have avoided some pretty significant problems by reading the instructions more carefully, and following the feedback you'd received before.

I understand that it's asking a lot, but this is unfortunately necessary - I'm going to have to ask you to complete the 250 cylinder challenge, in its entirety, again. When you're done, send it in as a new submission, which will cost you 1 credit.