Jumping right in with the form intersections, your work here is demonstrating a very well developed set of spatial reasoning skills. I'm not really seeing anything that stands out as a mistake, or really anything to call out at all - so I think it's safe to say that your grasp of this one has developed nicely. Continuing onto the cylinders in boxes, this is largely the same, except for one point which I had mentioned at the end of my feedback for your cylinder challenge work:

I have just one small recommendation - when identifying the minor axes of your ellipses, right now you appear to be only drawing the one closer to the viewer back a short ways. Be sure to extend it all the way back with the other lines, so you can fully judge it against the other lines with which it is meant to converge. That'll ensure that you don't accidentally miss on that extra information when deciding what to adjust on the next page.

In this case it seems that neither of the minor axis lines are extended back with the other lines as they should be, so be sure to keep that in mind when practicing this exercise in the future.

Continuing onto the meant of the lesson... honestly your work here is phenomenal, and I could save myself a fair bit of time by calling it here. But to do so would be an anticlimactic end to your journey, and you've certainly earned more than that through your hard work, so we'll take some time to look at exactly what you did so well.

Starting with your form intersection vehicles, many students take this much farther than it's meant to go, but you kept your focus on exactly what it is meant to achieve. With our more detailed vehicle construction demos, it's easy to get the impression that we've turned the process on its head and changed it completely, from building things out from simple to complex, to laying out a forest of lines and connecting them into a concrete result only at the last step. This exercise helps us remind ourselves that we're still working from big to small - instead of building something out of toothpicks, we're still whittling down a block of wood, piece by piece, into something more detailed and complex. Your focus on simple, primitive structures and disregard of detail hit the nail on the head here, and I think that carries over into your more detailed vehicle constructions and helps you apply the methodology used there to greater effect.

Moving onto your detailed vehicle constructions, you've done an excellent job of making full use of the orthographic plans and structuring your approach around a series of clearly defined decisions. By pushing as much of that mental heavy lifting onto the orthographic plan, you freed your brain up to engage more fully with the process of building up a defined recipe - that is, the decisions made in your plan - in 3D space, step by step. You did a great job of maintaining proportions, and while I can see some little adjustments made on the fly (which I am certainly guilty of in my demos as well - though that's something I'll be addressing when the overhaul gets this far), for the purposes of these exercises, avoiding these will help you get the most out of the exercise itself, as leaving ourselves open to such adjustments helps a lot when it comes to creating a better end result, but it does diminish the training value of the exercise, which of course always comes back to the core focus of the course: spatial reasoning. Adjustments allow us to undermine the impression of solidity that we hold in our heads as we engage with our work, and so it can weaken the main goal which is to create this really strong understanding and belief in our minds that what we're drawing isn't just marks and shapes on a flat page, but rather a structure existing in some three dimensional world, where it is forced to abide by the laws of that world.

Of course, I'm very much nitpicking there, because I haven't much else to pick at! The only other thing I wanted to niptick at is to remember that within the bounds of this course, we want to try and stick to reserving our filled areas of solid black for cast shadows only (another thing my demos don't stick to completely, as this is a slight shift in direction we've made over the last few years, with the demos for this lesson being several years older than that). The thing to avoid is simply defaulting to filling in predefined spaces with solid black, without actually going through the spatial thinking of determining the actual shape of the cast shadow (or at least whether the shape would encompass the entirety of that particular surface). A cast shadow's shape defines the relationship in 3D space between the form casting it and the surface receiving it. It is very easy to fall into the trap of filling things in just to differentiate between a surface oriented one way versus another (which is more akin to form shading), and we mainly want to ensure that when drawing as intended for this course, that they stick as much as possible to what brings their thinking back around to 3D spatial reasoning.

One exception - although we use some rather tenuous means to make it adhere consistently with our "rules" and frame them as cast shadows anyway - is the interior of the car. Here we argue that being on the interior, the external structure casts shadows onto all of those surfaces, but this isn't strictly true since the window glass is transparent. Ultimately it just helps bring the construction together and flattens out the interior in a way that helps - but usually that's something we want to avoid (for example in wheel wells and in the gaps of the bumper area).

At the end of the day though, that's just how we approach our drawings for this course - outside of the course, you can make those decisions for yourself, as long as they are kept consistent within a piece (or as long as you have a particular reason for breaking that consistency). It's remarkable how many "rules" we adhere to can be validly broken as long as you've thought about why you're doing it, rather than doing so without consideration.

Anyway! I'll go ahead and mark this lesson - and with it, the entire Drawabox course - as complete. Congratulations!