Starting with your cylinders around arbitrary minor axes, nice work! There are a few things I look for, and you've nailed each one:

• You're taking your time to analyze and identify the "true" alignment of each ellipse (though I would recommend you draw those red minor axes so they penetrate through the whole ellipse, instead of just being partials - this will emphasize how a seemingly small deviation on a partial line can actually be more significant and may require more of your attention)

• You've incorporated a great deal of variation to the rates of foreshortening to your cylinders, which is great to see. I mean, I know it's in the assignment description, in bold, but.. you'd be surprised how many people ignore that.

• When it comes to the foreshortening, you've demonstrated a solid understanding of how the ellipses on either end change both in scale and degree. Aside from a few instances, I'm seeing a clear relationship between the scale shift and the shift in degree. Both of these shifts convey to the viewer how much foreshortening is being applied - but if you end up with a dramatic shift in scale and a minimal shift in degree (or the opposite, which we can see in cylinder 143 on page 29, where the degree shift is considerable but the shift in scale is pretty minimal), it creates a contradiction where there are signs of both dramatic and shallow foreshortening together. So there are a few cases of this, but overall you demonstrate a decent grasp of this and keep things pretty consistent.

There's just one minor issue I do want you to work on - and that's the execution of the ellipses themselves. You do appear to execute them a little hesitantly at times, which causes them to come out a little uneven or wobbly. Remember to execute those ellipses from your shoulder, using the ghosting method, focusing first and foremost on a confident execution. Accuracy is important, but it is secondary to ensuring the ellipses come out evenly shaped.

Continuing onto your cylinders in boxes, you are making progress here, but there's one main adjustment that needs to be made to get the most out of this exercise: you're checking your "true" minor axes, but they need to be extended along with the other lines. Because you're not doing that, you're not as consistent in catching issues where the minor axes are off.

This exercise basically focuses on training students to construct boxes that feature two opposite faces which are square in proportion. We do this by using the ellipses, and their line extensions (the minor axis and the two contact point lines) to test whether the ellipses themselves represent circles in 3D space. The closer those line extensions are to converging towards the box's own vanishing points, the closer the planes that enclose the ellipses are to representing squares in 3D space. So extending the lines fully so you can analyze their relationships and make adjustments accordingly is an important part of this process.

All in all, you're moving in the right direction, but keep these points in mind as you move forwards and be sure to incorporate these exercises into your regular warmup routine, along with everything else you've been introduced to throughout this course. I'll go ahead and mark this challenge as complete.