Starting with your cylinders around arbitrary minor axes, you've generally done a good job here. Your ellipses are a touch hesitant at times, but only slightly, so just continue to push yourself on executing your marks with a confident stroke, after the usual planning/preparation phases of the ghosting method. You're also doing a good job of checking your minor axis alignment quite fastidiously.

There's two main issues I want to call out here however:

• The first of these doesn't come up too often in this section (it's more prevalent in the next part, which we'll talk about soon), but on occasion here there are some cylinders where, like in 107, you end up with side edges that are entirely parallel on the page, rather than being drawn with any notable convergence towards a concrete vanishing point. In other words, it forces the vanishing point to "infinity" in the manner discussed back in Lesson 1. The thing is, we can't actually control where the vanishing point goes - we can only control the orientation of our desired cylinder, and in this section, we're really just rotating our cylinders randomly in 3D space. The thing is, we only end up with a vanishing point at infinity when the edges it governs in 3D space are oriented perpendicularly to the viewer's angle of sight - basically not slanting towards or away from them through the depth of the scene. Given that our cylinders are rotated randomly, we can pretty much presume that they'll never align so perfectly here, so we should always incorporate some convergence, even if it's only fairly slight. Now of course, this isn't an issue that came up a ton of the time in this section.

• The other point I wanted to talk about is the two ways in which our ellipses (the one closest to the viewer and the one farthest away) in a given cylinder change over the course of its length. These are the "scale" shift, where the far end is smaller overall than the end closest to the viewer, and the "degree" shift where the farther end is proportionally wider. The thing is, both of these "shifts" are manifestations of foreshortening. They're the signs our brain uses to understand how much of the given form exists in the "unseen" dimension of depth, and how much of its length actually exists on the page. For this reason, these shifts have to operate in tandem. As the scale shift becomes more significant, it needs to be matched with a similar shift in degree. If however we look at cases like 108, 111, 112, etc. we get a more noticeable shift in scale, while the degree remains roughly the same. While the viewer won't exactly know the reason for it, they will be able to tell that something is off. So, just be sure to keep this in mind going forward.

Now, moving onto your cylinders in boxes, this is unfortunately where that first point, about forcing your lines to being parallel on the page (and placing their vanishing points at infinity) becomes a real problem. 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.

Due to the fact that you've drawn all of these boxes with no concrete vanishing points (which cannot happen in perspective projection, as there is no "zero-point" perspective), the line extensions (which you've otherwise done correctly) can't actually give us any useful information. They require convergences in order to actually help us develop our sense of those proportions.

I should also mention that there are boxes where your lines appear to be extended in the wrong direction. There aren't a ton of them like this, but 99 is one case where it seems to me, based on the left side being the wider ellipse (and therefore probably being intended to be farther away), all three sets of lines (pink, blue, orange) are extended towards the viewer. Keep an eye out for that.

Unfortunately, as you've done this second part incorrectly, that section will need to be redone.