In the future, I'd definitely prefer something where I can scroll through the images at a larger size, so I can jump around more easily to identify trends and patterns in how you work.

Starting with the first section - the cylinders aroud an arbitrary minor axis, I definitely think you show a great deal of improvement and growth. You start out okay, but there's definitely a lack of confidence behind the choices you make and how you put your marks down. As you progress, your ellipses tighten up a great deal, and your overall markmaking improves a lot.

I am definitely concerned about how you apply your corrections/alignment checks however. It seems that you're purposely avoiding having the "correct" minor axis for the ellipse actually cut through the ellipse you're checking, and so you draw it so it starts at its edge and extends away. I'm not really sure why that is, but having your minor axis line actually bisect the ellipse is a critical part of ensuring that you can see the relationship between them, and will continue to help you improve.

There is another thing that I should mention, that you appear to be applying in many areas, though it's inconsistent enough that I don't think you're doing so intentionally. It's likely that your instincts are steering you correctly in this, but that having it clarified will help more moving forwards. It's about foreshortening - specifically how both the change in scale of the far ellipse compared to the closer one and the change in degree between both ends are parts of how foreshortening is applied to a cylinder. Basically as the far end of the ellipse gets further away from the viewer, that ellipse will get smaller in scale, while also getting wider. They will do so at the same rate.

The main thing I'm addressing here is that you understand both of these separately, but they're linked - you'll never see a situation where the degree doesn't change much, but the scale of the far ellipse shrinks down a lot. Keep that in mind, as it'll help you keep things feeling consistent and correct.

Moving onto your cylinders in boxes, you've done a pretty good job with these. Most of the boxes themselves appear to be tending more towards being properly square - that is, having two opposite faces that are proportionally square rather than rectangular, so the ellipses you place within them can represent proper circles. That's really the main focus of this exercise - learning not just an approach to position cylinders in a very specific 3D location and orientation, but to be able to keep them at the correct proportion.

The one thing you skipped here however was that you only extended the lines in one dimension. You appear not to have followed the instructions about this technique all that closely, as you totally missed the aspects of checking your ellipses' contact points and focused only on the minor axis. While you did still demonstrate a fair bit of growth over the set, you definitely would have benefited more.

Anyway, all in all you've done a pretty good job. I'll go ahead and mark this challenge as complete.