Starting with the structural aspect of this challenge, you've done a good job both in using your ellipse guide to allow for a slight bump in the profile of the wheel (which helps to make the structure appear more inflated, more like it'll land with a bounce rather than a heavy thunk), and you've generally been mindful of not only drawing the outward facing surfaces, but also the side planes of those same forms.

When it comes to the textural aspect of the challenge, your work is especially interesting. While you haven't quite applied the concept of implicit markmaking correctly (in terms of how it's explained back in Lesson 2), you have very clearly made a concerted attempt to apply it, and have experimented with different ways of thinking about how the marks you're choosing to draw relate to the existing structures. That's important - while this part of the challenge is admittedly something of a trap, pointing out to students tendencies to forget about certain concepts, leave them unpracticed in their warmups, and to avoid revisiting them as is very much necessary, most often what I see is that students will fall back to explicitly drawing/constructing every textural form.

While you certainly did do this towards the beginning, I can see clearly that you did realize this was not correct, and so there was definitely a shift towards figuring out what kinds of filled areas of solid black you should be drawing, and where they should be placed. So while it does still seem like you didn't review the material from Lesson 2 (or at least didn't as closely as you could have), I very much appreciate the fact that some of it stuck in your mind, and that you were trying to figure out how to apply it, rather than simply constructing every form in its entirety as if from rote memorization.

Now, in terms of applying this more correctly, one of the critical things to keep in mind is the difference between form shading and cast shadows. Form shading involves the surface of an object being lighter or darker based on its orientation in space - it'll be lighter when it's pointed towards the light source, and darker as it turns away from the light source. All there is in this equation is the surface itself, and the light source.

Cast shadows however involve three components - the light source, the form casting the shadow, and the surface upon which it is being cast. The shadow shape itself does not merely fill an existing shape in the construction, but rather involves designing a new shape and then filling it in. It's the design of this shape which conveys the relationship in 3D space between the form casting the shadow, and the surface receiving it. This is the reason we focus on cast shadows so much in this course, but not on form shading - it's that cast shadows actually establish the relationship in 3D space between different elements of our construction. They always exist in relation to one another, and they focus on establishing relationships in 3D space - just as the other tools we employ (such as contour lines, intersection lines, etc.) all focus on creating relationships in three dimensions of space.

One example of you applying this correctly - by which I mean, using cast shadows instead of form shading - is in your roulette wheel, specifically this section surrounding the center into which the roulette ball ultimately settles. There you've introduced new shapes and filled them in, rather than filling in the side planes. I should mention however that the way in which you've placed these cast shadows isn't entirely correct - you've got the shadow being cast inward towards the center, as though light were shining upon this object from all angles, rather than from a single consistent light source - but overall this is still moving in the right direction.

Contrast this against this example where you've been filling in the side planes of those large textural forms, which is more akin to form shading. This example on the other hand does seem to suggest that you're starting to think about cast shadows instead, but it's still somewhat inconsistent. As we get towards the top and bottom (like here) you lean more towards filling in the side planes, but here towards the middle, it appears as though you're trying to use your filled area of solid black as a shadow that is being cast onto the surrounding area.

By and large you're definitely moving in the right direction, but still have more room for improvement.

Another common concern to be aware of is the tendency for students to, when tackling textures that tend to feature more grooves/cracks/holes, to regard those things as being the textural forms in question. They're not, of course - a groove or a hole is an absence of form, a negative space, with the actual forms in question being the walls that surround it and cast shadows upon each other (as shown here in this diagram). Because the crack/groove/hole is the thing we actually ascribe a name to however, it's common for students to start thinking of them as the textural forms, and simply filling them in completely without considering exactly what shadows are being cast, and upon which surfaces.

The last thing I wanted to mention is that there are a lot of areas where you've leaned into the reflections we get with chrome/shiny surfaces. While this isn't incorrect, and there are a few demos earlier in the course where I do this myself, I did want to mention that it's probably something I'll be removing when I redo demos for those sections. Basically, texture is the result of forms being present on a surface - so you can think of it being a sort of spectrum from extremely smooth on one end (which results in those kinds of very distinct reflections), to being extremely irregular/bumpy/rough on the other. For the purposes of how we're exploring texture in this course, it makes more sense to simply leave those surfaces that are so smooth to the point of reflectiveness blank, rather than simulating the reflections themselves. This can help ensure that we always use those filled areas of solid black for cast shadows only, without the unnecessary confusion. But of course, this is just something I'm advising you to keep in mind, as these kinds of reflections have definitely been included in some of the demos, and so you're certainly not wrong in applying them as you have.

Anyway, I'll go ahead and mark this challenge as complete. When you've had a chance to review the material from Lesson 2 further (in particular I'd point you towards these reminders, you can continue on.