Your work here is, to put it simply, stellar. I'm fairly certain I'm going to have trouble finding issues to point out, but I will try my best.

Starting with your form intersections, you make them look easy. Your linework is precise, and while your box constructions upon closer inspection do have some convergence issues within given sets of parallel lines, it's only noticeable if you look more closely. The exercise as a whole has been executed with such confidence that it's easy to assume that it's perfect, and not give it a second glance. The intersections themselves - the core of Drawabox as a whole, really, being that they represent the spatial relationships we're working so hard to understand on an intuitive level - are exceptionally well thought out. You are missing the most complicated intersection - which is a cylinder intersecting with a sphere whilst offset from the sphere's center (as shown here), but I don't doubt that you'd nail that too.

Now, admittedly your first car's tragically been pulled into a wormhole off to the right side, stretching out its proportions. I'm not sure if you did a proportional study elsewhere beforehand (based on the numbering of the grid along the bottom you probably did, but if it was going to stretch all the way back to 8, the proportional study may itself be at fault). Either way, the front of the car and that front wheel were very nicely constructed. Great sense of solidity, and the specific characteristics of the headlights, grill and bumper were nailed down well.

The rest of your cars came out great - I see that you purposely chose a limo (maybe you were self-conscious about your stretchmobile and decided to lean into it), but you handled the proportions much better here. I do think that the height is a little more exaggerated than it ought to be, but other than that it was well done. For some reason, the slight complexity to the doors, where their profile isn't entirely flat but rather incorporates that slight bump and dip really came out well. And once again, the wheel and front section all came out wonderfully.

Now while those cars were quite well done, the boat that follows is exceptionally well executed. The linework is confident and precise, and everything is broken down with such a sense of confidence - at no point do I see you exhibiting any signs of uncertainty or panic over subdivision gone awry - every mark serves a purpose, and all of your organic curves hold a sense of exactness.

The last one I'm going to talk about is your bus. On one hand, the plane at the end felt a lot more simplistic and less refined than the rest of your constructions, but the bus itself was well done aside from the fact that it feels somewhat.. slanted, or skewed. It seems to me that the actual windows of the bus in your reference may themselves have been parallelograms, resulting in the whole thing seeming strangely off kilter, but this isn't actually the main cause of the problem - just a contributing factor. The issue is that the front of the bus, specifically the windshield and the structure around it, was drawn without supporting elements. You established the front of the box itself that enclosed the bus as a whole, but the curving lines of that windshield were more arbitrary - the guesswork that drove them undermined the cohesiveness of the overall construction. If we are to cover up the front, the slanted windows themselves work somewhat better, but once we introduce the lopsided windshield, it emphasizes the intentional slant of the windows and pushes the whole bus off balance. To put it simply, unlike the boat where every curve was built off a foundation of precise straight lines, these were more arbitrary and the construction suffered for it.

So! I really took it out on that bus, but you've clearly shown yourself to have an incredibly solid grasp of the material both in this lesson and across the course in general. With that, I will happily mark this lesson complete. Congratulations on completing Drawabox. From here you can choose to tackle the entirely optional 100 treasure chest challenge, or you can go off on your own adventures.