Starting with your cylinders around arbitrary minor axes, as a whole you've done a pretty good job. Early on you ran into a couple issues, which I'll address in a second, but you did resolve them as you moved through the set.

The first of these issues is that those cylinders were being drawn, on that first page, with a lot of their side edges being basically parallel on the page. Not converging slowly, but rather being completely parallel with their vanishing point at infinity (as explained in Lesson 1). Sometimes students misunderstand, getting the impression that they can choose to put the vanishing point at infinity based on their own intent alone, but that is not the case. Instead, the only time where this is allowed (and required) is when the set of lines themselves are running perpendicular to the viewer's angle of sight. Basically if the lines are oriented such that they're going right across the viewer's field of view, then the vanishing point goes to infinity. Otherwise, there does need to be some visible convergence towards a concrete vanishing point.

The other issue there was simply that you weren't varying your foreshortening at all, as mentioned in the assignment section for the challenge.

I am glad that you addressed both of these issues, incorporating more concrete convergence and foreshortening and varying it considerably across the whole set. I'm also pleased to see that you appear to understand the relationship between the shift in scale (closer end being larger, farther end being smaller) and the shift in degree (closer end being narrower, farther end being wider) as it relates to foreshortening. It seems that you understood that these "shifts" need to work in sync - never being more dramatic in one, and shallower in the other. This is because they're both representative of the rate of foreshortening being applied to the given form, so of course they need to be similar in order to maintain a consistent illusion of 3D space.

Continuing onto your cylinders in boxes, you have similarly done a good job here, applying those line extensions quite conscientiously to analyze your results and work towards improving them with every page. The key focus of this exercise is to improve one's ability to construct boxes that feature two opposing faces which are square in proportion. We do this by using the cylinders themselves as part of the error-checking - basically if the cylinder's line extensions (minor axis, contact points) converge towards the box's own vanishing points, then this means that the ellipses represent circles in 3D space resting on the faces of the given box. If that's the case, then the face/plane enclosing a given ellipse is itself going to represent a square.

The closer we get to angling those line extensions in the right direction, the better we get at drawing this specific kind of box. This of course comes back to why this challenge is generally done between lessons 5 and 6 - being able to draw this particular kind of box is especially useful as we get into more geometric constructions. So, be sure to continue practicing it periodically as you work your way there, so you don't get rusty before it really comes into play.

I did want to call out one last thing - around cylinder-in-a-box 87, you mentioned that you were trying to do the boxes faster. Don't. At no point in this course should speed be a concern. Introducing your own independent goals and targets here will only serve to distract you from those of the course - and as you do that, you start to undermine the effectiveness of each assigned exercise. The course is designed to work with all these pieces in tandem - just let them do their thing, and continue to focus on executing each and every mark to the best of your current ability, with appropriate planning and followthrough. This means investing as much time as is needed in every area.

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