I see that you went with freehanding your wheels. Generally the larger, more versatile sets of ellipse guides (which allow for many different combinations of degrees and sizes) can be quite expensive, so as noted in this section we recommend that students pick up the more limited, but still very useful "master ellipse templates" instead. These have more limited size options, resulting in smaller wheels, but still help us ensure that we're not spending some of our limited cognitive resources on freehanding the marks, so more can be allocated towards the focus of the challenge. I'm working here under the assumption that you were not able to get your hands on a master ellipse template, and had no alternative but to freehand. Fortunately, your freehanding of the wheels came out quite well. As it's entirely normal for students to still need a lot more mileage with their ellipses, it's common for freehanded attempts to come out quite messy here, so it's fortunate that was not the case for you.

That said, keep this in mind as you go through my critique - while you executed those ellipses well, it does mean that you may have had less resources to put towards ensuring the exercise was done to the best of your current ability. I'll be calling out some issues, but always keep in mind that this splitting of cognitive resources could have contributed to them.

Starting with the structural aspect of the challenge, I'm pleased to see that you've constructed the body of your wheels with a nice, subtle arcing profile that results from the central cross-section of the wheel being larger than the outside. This helps to convey the impression that the tire is inflated, and that it would land with a bounce, rather than a heavy thud. When it comes to the spokes of your wheels' rims, you've generally handled them well in terms of being sure to define both the outward face as well as the side planes of the structure, although keep in mind that as explained back in Lesson 2, form shading should not be applied to our constructions throughout this course, in the interest of keeping the focus entirely on the core spatial relationships between the forms at play. As form shading only conveys the relationship between the light source and the form, they're not as useful to us here - and moreover, it can cause us to focus less on the construction to convey the illusion of 3D form. I don't feel that's the case here though (your form shading was more superficial, which is good), but do keep in mind that form shading should be left out (although you will see it in some of the older demonstrations, which are gradually being replaced to reflect the ways in which the course has changed to be more effective at its task).

Continuing onto the textural aspect of the challenge, here you've fallen into something of an intentional trap. It's very common for students to, being as far removed from Lesson 2 as we are, forget the concepts of implicit markmaking and the focus on cast shadows when dealing with texture. It also can speak to a greater tendency of students to allow certain concepts to be left behind as they progress through the course, rather than incorporating them into regular warmups. Texture is definitely the biggest case of this though.

Looking over your work, you've largely approached conveying the textures of your tire treads through explicit markmaking - that is, outlining the textural forms, or focusing more on form shading/filling in side planes. Always keep in mind that our goal with texture is to imply the presence of the forms. It is the shape of the shadow being cast, in the manner it is specifically designed, which conveys the relationship between the textural form in question, and the surfaces around it. Thus, the cast shadows themselves can provide enough information to understand the nature of the texture, while also not forcing us into maintaining a consistent density across the whole surface. Cast shadows can get larger or smaller based on the angle at which the light rays hit them (as demonstrated here, where the forms on the far right which are closer to the light source receive light at a much steeper angle and end up with a smaller cast shadow, and those farther to the left receive the light at a shallower angle, providing a longer, deeper shadow). This gives us the control we need to change that density as needed. Where in your wheels here, you had to draw every textural form in its entirety no matter where along the surface it was, the use of implicit markmaking via cast shadows would have put more of that control into your hands.

Now, one area where this can get a little tricky with tires in particular are those treads made up of shallower grooves. In these cases, some students may feel inclined to simply draw the grooves as lines, and the difference in the end result when approached in this manner instead of with the focus being on cast shadows can honestly be quite negligible. That does not make it the same however - the end results may be similar, or even identical, but these are exercises and so the focus is on how we're thinking about the problem as we solve it. These notes go into how we can think about these kinds of textures in more detail - it applies to things like grooves, holes, cracks, and so forth.

I am still going to be marking this challenge as complete - the "trap" is intentional, to serve as a bit of a reminder that there may be things you've allowed to slip through the cracks as you've progressed through the course, and as an opportunity to go back and review that material. To start, I would check out these reminders regarding textures, before reviewing the texture material more completely.