Jumping right in, you're certainly moving in the right direction, but there are a number of points I want to call out to ensure that you continue getting the most out of this exercise going forward. Based on what I'm seeing, I think there are certain kinds of textures where you're able to apply what you understand of the concepts more effectively, while others might lean into cases that emphasize where that understanding may be more tenuous - situations where you are more likely to fall into more common pitfalls and mistakes.

Those cases where you've got more obvious protruding textural forms - for example towards the beginning where you were dealing more with wrinkled skin/flesh, the gold ornament, etc. those kinds of textures give you very clear textural forms and structures, which leans more directly into thinking about the shadows those forms would cast. Still not easy, not by a long shot, but there's at least fewer spots students are likely to get confused and deviate from the instructions.

When it comes to cases that feature cracks and holes, your results were a bit more mixed. You handled the sandstone pretty well, in terms of focusing more on the walls surrounding the holes/pocks casting shadows onto the surfaces within them. While the use of stippling isn't wrong in this context (given the nature of the texture), I do still feel that you may have leveraged it as more of a shortcut to create the kind of gradient/transition which itself would be made up of smaller holes, where you would be expected to consider how the marks you put down relate to the forms/structures casting them, but where simply putting down a bunch of points would have been used as a way to avoid that.

While the sandstone was executed better as far as the larger holes go, for your dried clay and seaside rock, you fell back more into drawing the cracks you observed (with your shadow shapes being designed to reflect the cracks themselves, and not the shadows falling inside of them). This is something I noted towards the end of your 25 wheel challenge critique, where I shared this diagram and talked about textures involving grooves, cracks, and holes - while the outcome isn't necessarily going to be different most of the time, when we shift away from thinking about the 3D forms and the shadows they cast, and instead focus on drawing what we're observing within the reference directly, it causes us to fall into the traps and limitations of explicit markmaking - most notably, hindering our capacity to transition from sparse to dense detail.

Continuing onto your third page, the scale texture is one I wanted to briefly call out, because of your choices either relating to the arrangement of the scales themselves (meaning the direction in which they're layered and generally flow), or in regards to the placement of the light source. For the purposes of creating our gradient in this exercise, we're pretty strictly limited to placing the light source on the far right, causing all of our cast shadows being projected to the left. The further the forms casting the shadows are from the light source, the shallower the angle at which the light hits the object is, resulting in longer and longer cast shadows, as shown in this diagram.

When it comes to the arrangement of the scales, while you certainly can arrange them however you like, there are definitely some that make it easier to lean into the focus of the exercise, and some that make it harder. For the purposes here, I'd recommend having them flow horizontally.

Looking at the elephant skill, just a minor point to call out - since the cast shadows that make up our marks for this exercise are derived from the forms themselves, when we fixate too much on the shadows the patterns create, it can cause us to disconnect from what is actually meant to produce them. In this case, I'm not seeing any clear rolls of skin being defined between different cast shadows, and it feels more like each cluster of shadows is doing its own thing, rather than being the result of forms that might extend between different such clusters.

For the turtle shell, another point I won't spend too much time on - here it seems you've shifted more to drawing with individual lines in order to capture the successive ridges. This breaks away from the methodology we discuss in these reminders, where we want our cast shadows to be outlined and then filled, rather than being drawn line by line, because the latter leaves us more susceptible to simply drawing what we see, rather than actually considering and understanding the forms that are present, as they sit in 3D space.

Your bricks run into the same issue (drawing your shadows as lines instead of shapes), but you're also not really putting much into allowing those cast shadows to get significantly longer as they sit further and further from the light source. You're thinking more in terms of outlining the textural forms, which can be severely limiting when the goal is to create a gradient through cascading and lengthening shadows.

A minor note for the water drops - given their transparency, this does significantly complicate the exercise (especially considering that we're working with ink, so we're limited to black/white with no midtones), which can as you're still getting used to the basic application of it make things harder, so I'd recommend avoiding these kinds of complications when tackling this exercise.

I think I've touched on all of the points that are raised by individual instances of the exercise, so the last thing I wanted to call out is something that impacts them all: when practicing this exercise in the future, definitely try to push the dark side of the texture further. Towards the end, your "Pores in the tree" texture is definitely better at extending the dark portion and obfuscating the hard edge of that black bar, but this is done very minimally throughout the preceding pages, and in some cases you're not actually blending it in at all (deep crevices, turtle shell, dried clay, mutant flesh, alien skin, etc).

Anyway! That should cover all of the points I want you to keep in mind going forward. I'll go ahead and mark this optional challenge as complete. You are of course welcome to continue onto Lesson 7, although you'd technically cleared the prerequisites for that with the 25 wheel challenge already.