Starting with your cylinders around arbitrary minor axes, you have by and large done a good job here - you're drawing your side edges and ellipses with confidence so as to keep them straight/evenly shaped, and generally smooth, and you're doing a good job of checking your minor axis alignments in a fastidious, consistent manner that avoids assuming that an alignment is correct, so as to find even small mistakes and avoid plateauing in your growth.

There are two main things that I want to draw to your attention, so you can keep them in mind when working on this kind of exercise in the future:

• Avoid instances like 65 and 63 where your side edges converge towards a vanishing point that is forced to infinity. It's actually incorrect - we don't control the position of the vanishing point directly, just the intended orientation of the form (and therefore the individual sets of parallel edges), and it's that orientation which determines where the vanishing points would generally be. A vanishing point goes to infinity only when the set of edges it governs run perpendicularly to the viewer's angle of sight - so basically when they're not slanting towards or away from the viewer through the depth of the scene. For this challenge, we're rotating our cylinders arbitrarily in space, so while you could ostensibly get a few like this, in a sample size of 150 it's best we just leave them out altogether, and ensure that there is at least a little convergence to our side edges.

• Another point to keep in mind is that both the shift in scale from one end to the other, and the shift in degree, both are manifestations of foreshortening and they serve to tell us how much of the cylinder's length exists in the "unseen" dimension of depth (versus how much of its length can be seen right there on the page). This means that both shifts should occur in tandem. Try to avoid situations like cylinder 93, where the far end remains roughly the same degree as the closer end, while also being significantly smaller. In this case the far end should be a fair bit wider in its degree.

Continuing onto your cylinders in boxes, here you've also done fairly well. 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.

There are two points I want to call out here as well:

• Make sure that you're extending your lines in the right direction, as touched upon here in the box challenge notes. You generally did this correctly, but I did want to call this out because I noticed it number 242.

• Similarly, I only noticed one instance of this, but in the far end of 249, it looks like you only drew one of the two contact point lines. While this is obviously a minor thing to overlook one time, you wouldn't want to neglect this repeatedly as it is an important part of ensuring you're appropriately analyzing the results of your box/cylinder, so you can adjust your approach accordingly the next time to continue improving.

Anyway, all in all, good work. I'll go ahead and mark this challenge as complete.