Starting with your cylinders around arbitrary minor axes, I did find that towards the beginning of your set, you did tend more towards attempting to work without actual convergences, resulting in no actual foreshortening. This is something you did fix as you pushed through the set, so I'm pleased to see that, but I did want to address it further anyway.

So the thing to remember is that we don't get to just assert that "I'm going to put this vanishing point at infinity and eliminate any convergence for that set of lines" - whether a vanishing point is at infinity depends on the actual orientation of that set of lines in 3D space. If those lines run perpendicular to the viewer's angle of sight - basically if they're running straight across their field of view without slanting towards or away from them, then that vanishing point is going to be at infinity and those lines will continue to run parallel to one another even on the flat page.

In any other circumstance, even the slightest bit of slanting towards or away from the viewer through the depth of the scene, that vanishing point has to be concrete, and so those lines must converge when drawn on a flat page. Always keep that in mind when you push towards the shallower convergences.

Aside from that, your work on this section is fairly well done. You're pretty fastidious in checking the alignment of your ellipses (although I did catch at least one whose true alignment was quite drastically incorrect from what you marked down, so keep an eye on that).

The only other thing I wanted to share on this front is that your foreshortening manifests in two different ways, and they should be kept roughly consistent with one another. Those two ways are the shift in scale (where the far end gets smaller than the end closer to the viewer) and the shift in degree (where the far end). Make sure that you're actively thinking about, "well the convergence of my lines is more dramatic, causing the scale shift to be more significant, so I'm going to make that far end ellipse wider as a result" - or conversely, "the convergence is pretty minimal, resulting in a slight scale shift, so I'll only increase the width of the far end a little bit".

Moving onto your cylinders in boxes, I feel you've done a very solid job here, and I have just one tiny suggestion to make it better. You've been very consistent in extending your lines as needed - this is an integral part of this exercise, where the focus is ultimately to help students develop their instincts in regards to constructing boxes which feature two opposite faces which are proportionally square, regardless of how the form itself is rotated.

We achieve this by taking the line extensions from the box challenge and adding three more lines for each ellipse - the minor axis and the two contact point lines. In checking how far off they are from converging towards the box's own vanishing points, we're able to test how far off we are from those ellipses representing cirlces in 3D space, and therefore how far the planes themselves are from representing squares in 3D space.

The only slight suggestion I have is to make sure that you extend your minor axis lines as far back as everything else. I noticed that they tended to be shorter than the others, which could have made it a little harder to see whether they were converging consistently with the others.

Aside from that, you've done quite well. I'll go ahead and mark this challenge as complete.