Overall I'm definitely seeing a good deal of improvement when it comes to the quality of your ellipses. While you struggled a fair bit with the larger ones towards the beginning, this is something you definitely got better with throughout the set, all the way through the cylinders in boxes. Larger ellipses are admittedly quite a bit harder to do, but being mindful of drawing with your shoulder and doing so with confidence is importance, and it seems you've picked up on that.

Starting with the cylinders around arbitrary minor axes, I definitely see growth here with the specific focuses of this exercise. At the beginning, specifically the first page, I see numerous cases where you draw the far end ellipse with a degree that is narrower than the end closer to the viewer. As explained here, that relationship should be reversed, with the far end being the wider of the two. Now, you obviously caught onto this yourself, and corrected it as you moved through the set.

There is something else related to this however that I want to draw to your attention. It's something I leave for students to figure out for themselves, but some students don't quite pick up on it, so I'll explain it here. That degree shift, where as we move away from the viewer the ellipse gets wider, goes hand-in-hand with the standard scale-shift we're more used to (where the far end of an object gets smaller overall in scale as it moves away from the viewer. Both of these properties are aspects of foreshortening, and they're visual cues that tell us how much farther something is moving, and in turn, whether an object is larger or smaller. When the scale shift or degree shift are more dramatic, we assume a longer cylinder, and when the scale or degree shifts are more gentle and shallow, we assume a shorter cylinder.

Problems arise however in cases like cylinder 141 where we get a more dramatic shift in one aspect, and less in the other. Here we see a very dramatic shift in degree, but virtually no shift in scale. Conversely, the opposite is present in 112, where the degree shift is minimal, but the far end is much smaller than the nearer end. Both of these look off to the viewer, though they may not entirely understand why. It's important for this reason to keep those shifts consistent with one another.

Moving onto the cylinders in boxes, your work here is looking great. The thing about this exercise is that it's primarily about the boxes, rather than the cylinders. Specifically, it's about learning how to more intuitively construct boxes that have two opposite faces which are roughly square in their proportions.

In the box challenge, we employ line extensions to identify where our lines don't quite converge consistently towards the shared vanishing point, allowing us to make adjustments and try again, gradually improving our intuitive sense of how to better keep those convergences consistent. Here, we add the ellipses on either end of the cylinder to the mix, which gives us additional lines (the minor axis, the contact points, etc). Given that those lines only ever line up with the box's own vanishing points when the ellipses represent actual circles in 3D space (which are oriented to the faces of said box), this allows us to gradually work more towards boxes that will allow those ellipses to represent proper circles.

In this regard, you've done a pretty good job, and have shown a good deal of progress with those proportions throughout the set. While your boxes/cylinders do start out a little less congruent from the beginning, your lines definitely improve in terms of lining up with one another as you move on through, and those improved instincts for proportion will serve you well throughout lesson 6.

All things considered, I'm quite happy with your results. I'll go ahead and mark this lesson as complete.