Starting with your cylinders around arbitrary minor axes, your work here is coming along pretty well. You're executing your ellipses with confidence, maintaining nice, even shapes, and you're very fastidious in how you analyze your ellipses' "true" alignment, which grows more and more consistent over the course of the set.

I'm also pleased to see that you're incorporating plenty of varied foreshortening across the set, and you don't seem to be falling into the trap that some students do, of trying to eliminate foreshortening altogether.

There is one minor issue that I want to draw your attention to however. In our cylinders, foreshortening manifests through two distinct "shifts" between the two ellipses. There's the shift in scale, where due to the convergence of the side edges, the end closer to the viewer is larger overall, and the end farther away is smaller. Then there's the shift in degree, where the closer end is narrower, and the end farther away is wider.

The key point to keep in mind here is that since they both represent foreshortening, and therefore tell us whether there is, due to the cylinder's own orientation, either a lot or very little of its length that exists in the "hidden" dimension of depth (which we can't really perceive right on the page). The problem arises when one of these shifts is more dramatic, and the other is more limited - for example, if we look at cylinder 137 on this page, or even 140 on the same page, we've got ends that have roughly the same degree, but considerably different overall scale. The degree shift suggests that the length of the cylinder is pretty much what you see on the page, whereas the scale shift tells us that the cylinder is significantly longer in the dimension we cannot perceive. This leads to a visual contradiction.

So - always remember to keep those relationships from end to end consistent, so you're painting the same story regardless of which signs the viewer focuses on.

Moving onto the cylinders in boxes, you're moving in the right direction here, but there are a couple things for you to keep in mind. This exercise focuses on training students to develop a more intuitive grasp of proportion, as it exists in 3D space, and how it manifests when drawn in 2D. Basically, we're working to create boxes that feature two opposite sides which are proportionally square, rather than arbitrary rectangles.

We do this by incorporating the ellipses on either end of the cylinder - and specifically, their own line extensions (the minor axis and the contact point lines) into the line extensions introduced from the box challenge. This allows us to test whether the ellipses themselves represent circles in 3D space (the closer their lines are to converging towards the box's own vanishing points, the closer this is to being true), and in turn, whether the planes that enclose those ellipses represent squares in 3D space.

In this, you have certainly made progress, but there's two main issues:

• Firstly, when you end up working with longer boxes, you have a tendency to have a given set of lines separate into two groups, one for either end of the cylinder. You can see this in 155 and 158 on this page. If we look at the blue lines on 155 for example, we can see that there's two distinct groups. The red lines are a little better - since they're oriented a little more towards one another, they appear as though they probably are converging in a more consistent manner. Basically, when drawing these longer forms, pay special attention to how those lines are being oriented, and always think about how the linse you're drawing are meant to converge with all those others within their own set.

• Secondly, from what I can see, you do not appear to be extending your ellipses' minor axes along with all the other lines. Now, this doesn't inherently make the challenge fall apart, but it does diminish its effectiveness and can cause you to mess up proportions more significantly (like in 248 which gets quite narrow in one dimension) without address it in the analysis, so it can be accounted for in later cylinders. Make sure you keep on top of this when practicing this exercise in the future.

Anyway, all in all you are making good progress. There are a couple pitfalls to keep an eye on, but all in all, you're moving in the right direction. I'll go ahead and mark this challenge as complete.