Starting with your cylinders around arbitrary minor axes, your work here is generally moving in the right direction, although the point that stands out to me most is your linework. Generally speaking, it appears that you may not be investing as much time into the planning and preparation phases of the ghosting method as you should be (or perhaps not employing the technique at all). Remember that throughout the entirety of this course, every single mark you freehand - not just lines, but ellipses too - should be using the three stage process, focusing all of your time into the planning and preparation phases to improve your control/accuracy and ultimately executing your marks with confidence to ensure a smooth stroke. You're definitely executing your marks confidently, but I think a bit more time invested into planning your marks out, laying out those start/end points for your straight lines, etc. will help you achieve more consistent marks and help you nail your straight lines without the little gaps/deviations that we tend to see in your work here.

There are two other points I wanted to call out in regards to this section of the challenge. The first of these is to make sure that you're checking your minor axis lines more carefully. You're reasonably close in many, but there are definitely some (like 137 here) where the actual minor axis is quite a ways off. This is not an uncommon issue - it's just that if we're not focusing, we're going to be more inclined to think that our minor axis is closer to correct. So make sure you're paying full attention, and that you take breaks when you feel that attention waning.

The other point is that while you are definitely varying your rates of foreshortening in your cylinders here, I am frequently seeing instances where the side edges of your cylinders appear to run roughly parallel to one another in space, basically being governed by a vanishing point at infinity. Remember that a vanishing point only goes to infinity when the set of lines it governs run perpendicularly to the angle at which the viewer is looking out into the world - in other words, when those lines are running straight across their field of view, not slanting towards or away from them through the depth of the scene. Given that we're rotating our forms entirely randomly in this challenge, as we did in the box challenge, make sure you're always including some convergence to those side edges, even if it's fairly slight.

So, long story short - you're moving in the right direction here, but it does appear like you could stand to put more time into each individual cylinder, and each individual mark. Take more time, and remember that your responsibility in this course (as outlined here) is to give yourself as much time as you need to do the work to the best of your current ability.

Continuing onto your cylinders in boxes, the same points still apply, but all in all you're doing 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.

In checking your line extensions as thoroughly as you have here, you've been giving yourself ample information to work with, in order to find where your approach could be improved upon from page to page. As it stands, your sense for the proportion has definitely improved, although again - take more time, work through each step focusing only on what you're doing in the moment, and you'll get more out of these exercises as a whole.

I'll go ahead and mark this challenge as complete.