Starting with your cylinders around arbitrary minor axes, great work! You've done an excellent job of drawing your ellipses such that they remain confidently executed and evenly shaped, and you've been quite fastidious in checking your minor axis alignments - even identifying fairly minimal discrepancies, which will really help to avoid any plateauing in the "close enough" region. I can also see clear signs that you're using the ghosting method throughout - well, at least I can see it on the straight edges, with those visible points, but the impact of it is clear in all of your linework.

I'm also pleased to see that you've included a great deal of variety in your cylinders' foreshortening - and most importantly, whether this is the result of conscious understanding or just instincts aligning correctly, you are correctly increasing the shift in the degree of your ellipse as you increase the converge of those side edges - so basically as the far ellipse gets smaller in its overall scale, it's also getting wider, which is spot on. Both of these "shifts" (in scale and in degree) work together to convey to the viewer just how much foreshortening is being applied to the cylinder - in other words, just how much of the cylinder's length exists in the "unseen" dimension of depth, compared to how much is physically visible on the page. And so, if they operate independently of one another, the viewer will be able to pick up on it as appearing "off", even if they're not entirely sure why that is.

If your understanding of that was indeed instinctual, then hopefully my explanation will have solidified it - and if it was more conscious, then at the very least I'll have confirmed your own thoughts.

Continuing onto your cylinders in boxes, your fastidiousness has carried on here, and you've done a pretty solid job. 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 being as careful and intentional with your line extensions, specifically those relating to the ellipses themselves, you've done a great job of gradually adjusting your brain's understanding of those proportions, and while there is (as is perfectly normal) plenty of room for continued growth, I can see that your understanding of how to draw those boxes, regardless of how they're oriented, to achieve squared ends, has come along well. I expect this will serve you well as you move into the next lesson. The main thing I'd just encourage you to keep an eye on is the tendency, as your cylinders/boxes get longer, for the lines from either opposing side to group off into their own sets, rather than having all the lines from each side converge consistently. In the case of the box alone, this would be a matter of those edges converging in pairs, rather than all 4 at once - but of course, each ellipse adds its own lines to that.

So, all in all, good stuff. I'll go ahead and mark this challenge as complete. Keep up the good work.