Overall you've done a pretty good job with thee challenge, although as is pretty normal with this one, there are a number of things I can suggest to ensure that you continue getting the most out of this exercise as you practice it going forwards.

The main focus of texture as we use it in this course ultimately still comes down to the same underlying spatial reasoning concepts we explore throughout our constructional drawings. It's all about understanding the nature of the form casting the shadow, and then designing that shadow based on the casting form's relationship with the surfaces around it. There are a number of examples throughout your work here that demonstrate this being applied well (the feathers for instance demonstrate a clear focus on the relationship between the forms and the shadows they cast, although I would note that you appear to be casting them from left to right, which would definitely give you some trouble given that for these the light source is positioned at the far right).

There are however cases where you may be focusing more on the texture itself (in terms of the result you want to achieve), instead of the individual components that combine to create that result, and it can push you away from thinking quite as much in terms of the relationship between those forms and the shadows they cast. For example, as shown here, the edge of each shadow shape closest to the light source does imply the shape/silhouette of the form casting it (since the surface receiving the shadow is very close, meaning the given tuft of fur would block part of the shadow from view and stand out against it), but you've drawn both sides of the shadow shape with a similar kind of arbitrary zigzag. If however we know the shape of the tuft casting it, then the far edge of the shadow should correspond to it. I'm assuming that you were thinking about this one in terms of the shadow being cast from left to right (as seems to be the case across most of your textures), but ultimately the issue is the same - I just opted to demonstrate it from the more correct orientation.

Another case that stood out to me was your elephant skin, primarily because this is a case where what you're drawing appears to be more akin to the cracks/pits in the elephant's skin, entirely filled in, rather than them representing the shadows those forms cast. This relates to something I shared with you in my feedback for your wheel challenge, discussing textures involving grooves/cracks and other cases of "negative" space. This is the diagram I shared with you then, although I'd advise you to go back over the additional advice I provided in that critique. The other textures on that page - the crocodile skin, as well as the old tire, also feature this issue - you end up moving away from thinking about the actual 3D forms that are present, and more about the result you want to achieve.

Something worth considering is the actual kinds of textures that we choose for exercises like this. For example, the wheel texture on this page isn't really a single continuous texture - it's made up of different arrangements of forms. That isn't necessarily a deal-breaker, but when you lay it out as you did here (as zoomed in as you are), you had no choice but to leave massive gaps between the textural forms and the shadows they might cast. I expect this was because the wheel itself is narrow, giving you minimal options across the width of the wheel, but we're not necessarily locked into that. We can opt to lay out the wheel's texture lengthwise (unwrapping it from the cylinder and laying it flat, which would give you considerably more space), or you can just have the textural forms repeat - artificially widening that surface based on the forms that are there - and zooming out so you have plenty of textural forms to work with to create your gradient. Of course, this kind of modification is easier to perform when you're dealing with a simpler texture with just one repeating arrangement of forms.

Looking at the leaf texture on this page, this is actually a texture that we have a bit of an example for in the demo for the leaves exercise. What it demonstrates is that as our gradient reaches towards the light source, the cast shadows that still remain are those "trapped" in the joints where a vein branches off into several. So the result is a bunch of V's, whose arms taper off along the straightaways until they hit another juncture. This is also an application of what's demonstrated in the bottom of the diagram here, where it talks about "lost and found edges" and how deeper cracks where forms meet retain their shadows.

Ultimately the most important thing to keep in mind is that this exercise is not one where we should be worried about the end result we want to achieve. It can be a little difficult to remind ourselves of that, since we're looking at reference images that can, to varying degrees, suggest what kinds of results we are aiming for, but it's important to avoid thinking of them in those terms. Instead, view the reference images as a source of information, where we identify the kinds of textural forms we're playing with, how they're arranged across a given surface so we can use them for our own purposes. At the end of the day though, what we draw and what we think about drawing always comes down to cast shadows.

This diagram demonstrates this notion:

• First in the traceover of the reference image, we're identifying the kinds of forms that are present and how they vary/how they're similar.

• Then in the first rectangle labeled "the forms we're transferring" this is more of an idea of how we would, in our heads, think about arranging those textural forms on our surface based on what we saw in the reference.

• Next in the rectangle labeled "how we're thinking about the cast shadows" are the actual lines we'd be drawing to design those cast shadow shapes, based on our understanding of the relationship between each textural form and the surfaces around it. The forms from the previous step are faded out here, because again - they weren't drawn. This is definitely the most challenging part, because working implicitly requires us to think about multiple forms simultaneously without drawing them - though not all at once, more a small handful including the one whose shadow you wish to design, and those whose surfaces that shadow might touch.

• And finally, we'd fill in those shadow shapes.

Anyway, I'll leave you with that, and will mark this challenge as complete.