This lesson is definitely a struggle, and asks a lot - but I'm thrilled to see that you gave yourself the time you needed, and that you've met the challenge head-on.

Jumping right in with your form intersections, by and large you're doing pretty well here, but there are a couple of little hiccups I wanted to call out:

Continuing on, your cylinders in boxes are looking good, but don't limit yourself to really shallow foreshortening. Play with somewhat more dramatic convergences as well.

For your form intersection vehicles, it's not uncommon to see students take these waaay farther than they need to building up more detail than was strictly assigned. While you didn't go into more detail than was necessary (you stuck nicely to the core forms), you definitely did put a lot more into plotting them out with precision than you really needed to. It's definitely not a problem - I mean, you did a great job, and were very meticulous - though this exercise was really just the same as the form intersections, but with the forms arranged in a particular fashion. No need to fuss over the proportions so much in the future, that's more the realm of the later drawings for this lesson.

And, needless to say, you've done an excellent job building up each of your more detailed constructions as well! You've woried through a wide variety of vehicles here, and with each one you've applied the same core principles. I really don't see you skipping any steps. In fact, there are some little areas where the way in which you're thinking through how the constructions are being 'carved out' shows through - for example, how we can see the box you'd used for this car's hood, before then cutting into it in three dimensions to give it that downward slant. Very nice work.

As far as your constructions go, your work here is stellar. But I do have one admittedly small recommendation, and it has to do with your windows. We do generally go with the rule of thumb that our filled areas of solid black should be reserved for cast shadows, but that isn't actually a problem here. Being that we're using those filled areas of solid black for the interior of our vehicles, where ostensibly one could argue that they're having shadows being cast by the structure of the vehicle upon the surfaces inside it, we are kind of still following that rule. But this can be done better by actually being mindful of what surfaces exist inside of the vehicle, rather than simply filling in the surface of the window as a whole.

Of course, this is best demonstrated rather than explained. As you can see here on your jet, carving out the structures inside the cockpit and allowing the glass on the other side to remain white gives us a far greater sense of depth and structure for the plane as a whole.

There are definitely some windows that would unavoidably be filled in (like most of those on the train, aside from the one farthest to the right through which we'd be able to see through the other window), but it's important to avoid filling these things in without thinking through how the marks you're putting down relate to what you're placing in the 3D world. If we fill the windows in completely, then it's not taking the interior into consideration, and therefore we're actually painting the windows' surfaces themselves black - which would be a little odd.

Aside from that, your work is absolutely phenomenal. So, I'll happily mark this lesson, and the entirety of the course with it, as complete. Congratulations on getting through Drawabox, and I wish you the best of luck with whatever it is you intend to pursue next.