Starting with your form intersections, the intersections themselves are demonstrating a well developing understanding of how these forms relate to one another in 3D space. I have made some corrections here to your first page, but these are mostly small tweaks to intersections whose general behaviour were largely already headed in the right direction. That said, there are some other concerns not specifically related to the intersections themselves, but rather remembering to do things like draw through ellipses, keep your foreshortening shallow in this exercise as discussed here, and to ensure that the degree shift on your cylinders keeps up with the scale shift (something I mentioned when critiquing your cylinder challenge), so do be sure to keep an eye on those things.

The other point I wanted to mention is that the way you've packed some forms together quite tightly (as we see here for instance) isn't something I'd recommend. Difficulty for difficulty's sake isn't inherently valuable - it can become distracting, and often does. It also makes it harder on our end, so there's little benefit to it. I'd definitely recommend avoiding having quite so many forms overlapping together in the future.

Overall I do think you're demonstrating a well developing understanding of the intersections themselves and the spatial relationships they represent - but still, I wanted to share this diagram with you, not because you need it, but because there's no sense in depriving you of it. It explains how approaching these more complex intersections, especially those involving curving surfaces, requires us to think about each individual surface and consider how they're each moving through space. It also looks at curving surfaces through a different lens, framing them around being a gradual transition between different surfaces, similarly to what a sharp edge does more immediately.

Continuing onto your object constructions, I think you've done a pretty solid job and have done well to keep the focus on the heart of the lesson itself: the concept of precision. Precision is often conflated with accuracy, but they're actually two different things (at least insofar as I use the terms here). Where accuracy speaks to how close you were to executing the mark you intended to, precision actually has nothing to do with putting the mark down on the page. It's about the steps you take beforehand to declare those intentions.

So for example, if we look at the ghosting method, when going through the planning phase of a straight line, we can place a start/end point down. This increases the precision of our drawing, by declaring what we intend to do. From there the mark may miss those points, or it may nail them, it may overshoot, or whatever else - but prior to any of that, we have declared our intent, explaining our thought process, and in so doing, ensuring that we ourselves are acting on that clearly defined intent, rather than just putting marks down and then figuring things out as we go.

In our constructions here, we build up precision primarily through the use of the subdivisions. These allow us to meaningfully study the proportions of our intended object in two dimensions with an orthographic study, then apply those same proportions to the object in three dimensions.

I definitely see a lot of cases where you leverage these orthographic plans to great effect, although I do think that as you continue forwards, there are opportunities to make better use of them as well. This lighter for instance stood out to me in a number of ways:

• I can see that you leveraged subdivision to an extent, but it was fairly light, leaving a number of important landmarks undefined, and therefore having to be approximated during the 3D construction.

• While not everything needs to be defined fully through subdivision, at least ensuring things are symmetrical by using mirroring is well worth it.

• I noticed that you did not construct the lighter using a bounding box, which makes a lot of the subdivision you did employ somewhat harder to apply. The precision we get from our orthographic plans only really translates to the construction if we're using the same methodology. Think of it like the orthographic plan is the recipe - you figure it out, make all of your decisions up front, so that when you build it out in 3D, you can focus only on repeating the procedure you've concocted, rather than having to actively make a bunch of decisions along the way.

Now I do think that these issues were more present earlier on, but as you got more accustomed to the use of the tools described throughout the lesson, your capacity and willingness to use them definitely expanded, resulting in much stronger examples further into the set. This one in particular really shows that kind of precision I'm talking about.

One thing in there that I did see you struggling with a bit was the curve. I can see a broad attempt at using the concepts explained here, but I think that breaking it down further as we see here would definitely have helped.

Anyway! All in all, you're very much headed in the right direction. I'll go ahead and mark this lesson as complete.