Starting with your cylinders around arbitrary minor axes, your work here is looking quite solid. Your linework shows a clear adherence to the core principles of the ghosting method (resulting in confident and smooth linework, as well as evenly shaped ellipses), and you're quite fastidious in your checking of the ellipses' alignments, catching even small discrepancies to ensure you don't plateau in your growth by becoming complacent. One small thing I would call out is be sure that you are drawing around the elliptical shape two full times, as required back in Lesson 1. It's clear that you intend to, but you may have gotten a little too used to it, and as a result have a number of spots where you only draw around the shape one and a half times, rather than the full two.

Carrying onto your cylinders in boxes, your work here is similarly well done, save for one very small point that I'll call out in a moment. 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.

You're doing an excellent job with this, but there is one place where you're not quite applying the line extensions as correctly as you could be. Currently you're only "identifying" your minor axes, in the manner instructed for the previous section. This leaves you with shorter lines for those minor axes, rather than full line extensions that would allow us to compare them more easily with the other lines and their implied vanishing points. So, when practicing this exercise in the future, be sure to extend them all the way back, as shown in the instructions.

With that, I'll go ahead and mark this challenge as complete. Keep up the great work!