Starting with your arrows, they're definitely flowing quite nicely through 3D space. One thing you may want to keep in mind however is that you want to keep the rate at which the ribbon itself gets narrower (as it moves back in space) consistent with the rate at which the spacing between the zigzagging sections tightens up. This is because perspective applies to both positive and negative space consistently - it applies both to the size of objects, and the distances between them.

Moving onto your organic forms with contour lines, you've done a great job! You're sticking to simple sausage forms, you're drawing your contour ellipses and contour curves with confidence, keeping those shapes nice and even/rounded, and you're clearly mindful of how the degree of your contour lines shifts.

Your work on the texture analyses is similarly well done - to start you're definitely more focused on flat, graphic shapes, but you steadily start to think more about how the way in which your shadow shapes are carved and designed implies three dimensional structure to the textural forms being implied, and by the end you're really knocking it out of the park. On top of that, and throughout the whole exercise you're demonstrating exceptiona attention to detail and strong observational skills. This carries over into your dissections all the way through, although I have just one minor point to raise about your cobblestone texture. Don't fall into the trap of filling the negative space - that is, the space between your main textural forms - with black. Shadow shapes relate directly to the forms casting them, and they fall onto surfaces that are similarly otherwise white/blank. It's the forms that block the light from reaching them, and when we fill those negative spaces in, we lose that sense of dimension.

Also, for the pangolin scales, it can be easy to slip back into the habit of outlining forms when there's these discrete textural forms - so just make sure you're still reminding yourself to work exclusively with cast shadows.

Continuing on, your form intersections are very well done. You've drawn the forms such that they (mostly) feel cohesive and consistent with one another, except for cylinder at the bottom of this page. Remember that the instructions state that you should avoid forms that are more stretched in any one dimension - stick to those that are equal in all three dimensions (roughly so). This is specifically to avoid making this exercise more complicated than it needs to be with the introduction of foreshortening. That's ultimately what went wrong with that cylinder - it's more foreshortened than everything else, which threw off the sense of scale relative to the other forms.

One other point - make sure you're drawing through all of the ellipses you draw for these lessons without exception. This will help you keep your confidence up when drawing them, achieving a smoother, more even shape which in turn will help keep your forms feeling solid.

Lastly, your organic intersections are very well done. You've drawn them such that they establish clear interaction in 3D space, instead of looking like flat shapes stacked on a page. You've also sold a strong illusion of gravity, capturing how those forms slump and sag over one another.

All in all, your work here is fantastic. I'll go ahead and mark this lesson as complete.