Starting with the structural aspect of the wheels, you've done a pretty solid job in the use of your ellipse guide to create a profile for your wheels that incorporates a subtle arc. This helps a great deal in making the tire itself feel more inflated, as though the wheel would land with a bounce rather than a heavy thud. When it comes to building out some of the other structures of the wheel - for example, the spokes of the rims - I am noticing that you definitely take some leeway to be a bit looser with your linework here, and don't adhere as strictly to the principles of mark making from Lesson 1 as you should. I don't doubt that you certainly can, but you definitely made a clear decision here when it comes to your smaller and more repetitive marks that they were not necessarily worth investing all of the time you could have.

To that point, I do want to remind you that as discussed here in Lesson 0, it is important in terms of getting all you can out of this course that you do commit that time to ensure what you're putting forward is the best of your current ability.

Carrying onto the textural aspect of this challenge - that is, dealing with the tire treads, which are made up of individual forms arranged along the surface of a larger object, which lines up quite well with how we define texture in this course - this challenge is something of a trap. Being as far removed from Lesson 2 as we are, it's not at all uncommon for students to simply forget that those concepts exist, and so those students have a tendency to neglect them here. While I won't say that you're neglecting them completely here, as there are signs that you're attempting to apply certain elements, overall there is a lot that you will want to review to refresh your memory on how we engage with texture here.

There are a few considerations here. The first of these is that when drawing your textures, I can definitely see that you're trying not to outline the entirety of your textural forms (perhaps in an attempt to avoid explicit markmaking). What you're doing instead is putting down some of those explicit marks, but just not outlining your textural forms in their entirety. So in a sense, you're still heading down the path of explicit markmaking, but somewhat randomly are deciding not to draw some of those marks.

What Lesson 2 explains is that you're not actually supposed to be drawing those textural forms directly. Rather, you're to draw the shadows they cast on their surroundings, using those shadows and the way their shapes are designed, to imply the presence of the form casting them, and their relationship with the surface upon which those shadows are cast. To put it simply - we're not constructing our textural forms, we're only drawing their shadows. This is very different from simply drawing some-but-not-all of the outlines of those forms.

To illustrate this point further, take a look at this breakdown of how we might apply the texture analysis exercise from Lesson 2 to a melted wax texture. As shown here, first we need to think about the actual forms that are present along the surface. Not in generalized terms - it can be tempting to just be vague, but that is not what we're after here. We want to think about specific forms, and generally you're not going to be able to keep them all straight in your head at the same time. Instead, you'll have to focus on subsections, where you've got one form casting a shadow, and the surfaces immediately around it receiving that shadow shape.

Keeping that in mind, you outline your desired shadow shapes based on your understanding of how those forms sit in space. Again - the shape of the shadows themselves is something you design in order to capture the relationship between the form casting it and the surface receiving it. And lastly, you fill those shadow shapes in. This also matches the reminders provided here in Lesson 2.

Another point to keep in mind is that there is a distinction between the cast shadows we're using here, and form shading. Looking at the example of 25 for instance, it looks like you were filling in some of the side planes of your textural forms. This would be more akin to form shading, where the surface gets lighter or darker based on its orientation in space. Whereas cast shadows will generally require you to design a new shape, rather than filling in an existing one. So if you ever catch yourself being inclined to fill in an existing shape, stop and take a step back to assess whether you're really adding a cast shadow.

While we're still on the topic of cast shadows, one last thing to keep in mind is that approaching them in a two step process - first outlining/designing the shape, then filling it in - is important. I can see a lot of cases in your work where you jump into filling the shape without first having designed it, resulting in you "painting" the shadow in stroke by stroke, which tends to come out a bit sloppy.

Now the final point I wanted to call out is that when we deal with textures made up of grooves, holes, cracks, etc. we tend to think of those things I just listed as being the textural forms in question, since they're the things we can ascribe actual words or names to. But they're not forms, they're an absence of form - they're negative space, gaps cut into the structure. The actual forms in question would be the walls surrounding them, which cast shadows upon one another and upon the floor beneath. Keep this in mind - it may not always make a noticeable difference in the end result, but it does fundamentally change the way in which one might approach drawing a given texture - for example in 22, you attempted to capture the grooves by drawing lines to follow their path, rather than focusing on understanding the forms as they exist in 3D space, and how they cast shadows upon one another. These notes go into this a bit further.

I definitely think you'll stand to gain a lot by reviewing the texture material in lesson 2, but ultimately the challenge has served its purpose (to be a sharp reminder of the fact that certain concepts had been left to be forgotten). So, I will still be marking this challenge as complete.