Overall your work here is really quite solid, although there are a couple points I can suggest to help you continue to improve in your practice of this exercise. Primarily though, I am fairly confident that you're picking up on the core concepts of texture as it's taught in this course, and you're applying it pretty well.

So there's two main concerns present, although both do have examples where they're done better, and cases where they're more of an issue. The first one has to do with the solid black bar along the left side of our texture gradients. In many cases throughout your set you handle this well, transitioning smoothly from solid black into your texture - for example, these from the beginning show a lot of attention being paid to how we flow slowly and gradually from dark to light, with no clear point at which the solid black bar ends and the texture begins. Later into the set however, like on this page, we see more instances of the bar being left solid and clearly defined, transitioning much more suddenly into the texture.

Now, in cases such as those it's clear that you overlooked the necessity of this consideration, so correcting that is just a matter of remembering the purpose of the black bar. There are some other cases that are somewhere in the middle however, like those we see here where you do have a transition from dark into the texture rather than a very solid line, but it's compressed into a tiny space, resulting in a jump that isn't completely sudden, but it is still a little jarring. In such cases, try to spread out the "dark" across more of your texture to make the transition more gradual.

The second point I wanted to raise has to do with how you handle your marks on the other side, closer to the white extreme on the right side of the gradient. This is actually mentioned in the bottom of this diagram from the notes, but as it's buried in the diagram it's easy to miss. When we decide which marks to make when drawing those forms which are only barely implied by the smallest of shadows, we can often find ourselves "guessing" at which shadows to leave in, and which to leave out. Ultimately it all comes down to the fact that these are cast shadows, and so how they behave is always subject to the relationships between the forms that are present, and the light shining across them.

Shadows will tend to get "trapped" and be more stubborn when they're caught in the corners where different forms meet, while those that are left out in the open will easily be burned away by the light. So, if you've got a bunch of rocks that are piled together, where those rocks meet, the shadows will be more "protected". Where the form extends away from the group however, it's more vulnerable. This gives us a sort of hierarchy to work from when deciding which shadows will disappear sooner, and can save us from trying to guess at it or end up with marks that appear more like broken lines, rather than actual concrete shadows.

To this point, remember what's mentioned here in these reminders from the texture section - it's all about looking at our reference and understanding how they relate to the forms around them, rather than simply copying what we see. Your work suggests that you understand this, but it is in the areas that we are least confident - like how to approach the cases with the fewest marks being used to imply our forms - that we can fall back to old strategies.

Anyway, I'll go ahead and mark this challenge as complete. All in all, you've done an excellent job, so keep up the good work.