Very nice work! I can definitely see throughout the whole set that your attention to structural detail - that is, the construction itself - is exceptionally well done. I do understand the limitations of the cheaper master ellipse templates, both in terms of scale and the degrees available. In truth, either option (an extreme degree shift or none at all) would be acceptable. Being that these wheels aren't particularly large, we can certainly see them having minimal foreshortening applied to them, but more dramatic foreshortening is also acceptable since we could be looking at them particularly close. Either way, neither option impedes the purposes of this challenge, and it all falls within an acceptable range.

Looking at those structural elements, I'm very pleased to see a number of things:

• Most of your wheels have a nice swell through their midsection, allowing them to feel more inflated, rather than like the more solid cylinder we see in wheel 1. In some cases this means widening through the middle, but there are others (like 14) where a subtler bevel towards the ends is more appropriate. You did a good job of paying attention to your references, and applying the variation that was necessary.

• You paid a lot of attention to the construction of the spokes/rims. I'm especially pleased to see that you were always mindful of defining not only the front plane (facing outwards from the wheel), but also the side planes of those structures, allowing them each to feel solid and three dimensional. In terms of the spacing of those spokes, most of these are also very well done - although 6 looks a little skewed, almost as though it's meant to have an extra spoke to fill the gap. Looking at your reference, I can see what you were going for, and spacing them out a little further would definitely have helped.

Continuing onto the other half of the challenge - the use of texture when capturing the tire treads themselves - I am happy to see that you did not entirely forget about the texture section from Lesson 2, and its emphasis on the use of cast shadows, as many students do. That said, you didn't apply its principles of implicit markmaking vs. explicit markmaking as thoroughly as you could have. While you did ensure that the larger, chunkier textural forms cast shadows on their surroundings, it still appears that you did first outline them in some capacity.

I totally understand - jumping right into the cast shadows is really hard, and it requires us to maintain a fairly complete understanding of a specific textural form in our minds, before we make our marks, and that is an extremely challenging and time-consuming thing to ask. If, however, we fall back to using outlines (even partially as you've done here), we rob ourselves of the opportunity to practice that skill. These drawings, pretty as they are, are not about ensuring success of a final result. They are, each of them, exercises. Opportunities to make mistakes, and to build those skills, bit by bit.

This isn't so much of a concern for the shallower tire treads, where the grooves can be represented with lines. Those were handled well, and in general regardless of the type of texture you did show a fairly specific awareness of how every textural form exists as a three dimensional structure, and of how even those very shallow grooves are actually textures made up of the forms that surround those grooves. Overall, you're progressing well, but do be sure to review the texture material from Lesson 2, and to continue practicing this on your own. While it seems superficial, this is all about understanding 3D spatial relationships, just like construction - only at a smaller scale, and in a different context. Tackling these same problems in many different ways will only serve to further flesh out our core understanding of the concept.

So! Great work overall. I'll go ahead and mark this lesson as complete.