Starting with your cylinders around arbitrary minor axes, your work here is very well done. It's clear that you've been quite fastidious with checking your alignments, and overall you've been keeping them quite accurate. I'm also pleased to see that you included a wide variety of foreshortenings throughout this set, which allows me to analyze what you understand about the way in which the ellipses change from one end to the other.

From what I can see, you've been correctly increasing the amount by which the degree changes (the far end getting wider) with how much the scale changes (the far end getting smaller). This is actually something a lot of students don't pick up on, that both "shifts" will occur in equal measure, and that we'll never see a case where the far end is dramatically smaller, but where the degree remains the same, or vice versa.

Moving onto your cylinders in boxes, you've also been quite thorough in applying your line extensions here, and to great effect. The purpose of this exercise is to help students develop their ability to construct boxes that feature two opposite faces which are proportionally square. We do this by taking the line extensions from the box challenge, and adding the lines from the ellipses themselves - the minor axes and contact point lines. When these lines align to the box's own vanishing points, then it means the ellipse fitted into the face represents a proper circle, and therefore the face enclosing it represents a square in 3D space.

By practicing this with the line extensions, we steadily make adjustments to our approach to drawing these boxes, ultimately improving our instincts for proportions. It seems clear to me that your proportions have indeed improved throughout the set - as have your boxes in general. This should help you a great deal throughout the next lesson.

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