Starting with your organic forms with contour lines, these are largely well done. You're sticking closely to the characteristics of simple sausages as defined in the instructions. Your contour curves could be drawn with a little more confidence (right now you're hesitating just a little bit, favouring accuracy over achieving a smooth, consistent stroke), but they're still coming along quite well. The only other thing to keep an eye on is that the contour curves themselves should be getting wider as we slide along the sausage form away from the viewer. Right now you've got them staying pretty consistent in their width, except when you need them to bend. There's a demonstration of why the degree shifts as it does in the lesson 1 ellipses video, so be sure to give that another look.

Moving into your insect constructions, your results here are a little mixed. There's definitely improvement over the course of the set, and frankly there are key signs that at your core, things are definitely starting to click for you. Specifically, I can see that you're thinking more and more in terms of how the things you're drawing exist in 3D space as solid, tangible things, rather than just lines on a flat page. There are however a lot of choices that you're making in how you approach drawing those forms that work against you as well. Once we sort that out, I think the core underlying grasp will shine through, and you should yield stronger results.

The key thing to always remember is that because we're drawing on a flat piece of paper, we have a lot of freedom to make whatever marks we choose - it just so happens that the majority of those marks will contradict the illusion you're trying to create and remind the viewer that they're just looking at a series of lines on a flat piece of paper. In order to avoid this and stick only to the marks that reinforce the illusion we're creating, we can force ourselves to adhere to certain rules as we build up our constructions. Rules that respect the solidity of our construction.

One rule that we must follow, is simply to treat everything we draw as though it were something that actually existed in this 3D world, alongside everything else we've drawn as part of a given construction. That means that we cannot simply have different forms that occupy the same space, ignoring one another - even though we could ostensibly draw them in such a way that they exist entirely separately. For example, if you look at this construction, I've highlighted two distinct forms, in red and blue, that appear to exist simultaneously in the same space but do not respond or react to one another at all.

Another important one is that once a form has been drawn, we cannot go back in and alter its silhouette - not without flattening it out at least. Its silhouette is just a shape on the page which represents the form we're drawing, but its connection to that form is entirely based on its current shape. If you change that shape, you won't alter the form it represents - you'll just break the connection, leaving yourself with a flat shape. We can see this most easily in this example of what happens when we cut back into the silhouette of a form - although any kind of alteration, including adding individual lines or partial shapes as you did here on this treehopper are similarly little shortcuts that attempt to change the nature of 3D structures whilst working strictly on the 2D drawing.

Instead, whenever we want to build upon our construction or change something, we can do so by introducing new 3D forms to the structure, and by establishing how those forms either connect or relate to what's already present in our 3D scene. We can do this either by defining the intersection between them with contour lines (like in lesson 2's form intersections exercise), or by wrapping the silhouette of the new form around the existing structure as shown here.

You can see this in practice in this beetle horn demo, as well as in this ant head demo. Now, you may recall that modifying silhouettes is precisely how we interacted with leaves and petals in Lesson 3 - but the reason we could is that they were already flat, as explained here. This is all part of accepting that everything we draw is 3D and has volume to it, and therefore needs to be treated as such in order for the viewer to believe in that lie.

I can actually already see a fair number of cases where you attempt to build on top of the sausage structures of your insects' legs - there you're trying to add new, completely enclosed structures to add bulk where it's needed and to capture more nuance in the given structure. This is great to see, and you're absolutely moving in the right direction. The only problem is that right now the shapes themselves are kind of arbitrary in how they're shaped, and they don't really define any clear relationships with the existing 3D structure they're attaching to. Instead, they feel more like flat stickers being pasted on top of the drawing.

Instead, we can take more care in actually designing the silhouettes of these new forms such that the silhouette's shape actually shows how they wrap around the existing structure. This diagram which I linked earlier definitely helps with this. It can be applied as shown here in a more general sense, and here's how it'd look when applying it to the leg structures.

Here it is in action with an ant's leg, and here it is with a dog's leg (as this is an approach we'll continue to use well into the next lesson when tackling our animals).

Speaking of the sausage method, I am pleased to see that you're making a clear effort to apply it to your constructions. There are a few places where you miss certain steps (like reinforcing the joints between segments with contour lines) or where you deviate from the characteristics of simple sausages, but for the most part you're employing this technique well. Just be sure to review the sausage method diagram every now and then to make sure all of its elements are being applied consistently.

Now, I do feel you're moving in the right direction as a whole, but I would like to give you the opportunity to apply the points I've raised here before you move on. I want to make sure that you understand what I've explained, and that you're able to demonstrate that through its use. You'll find a few additional pages of revisions assigned below.