Starting with your organic forms with contour curves, you're largely handling these quite well. The contour curves are drawn confidently, so as to achieve a smooth, more even shape, and you're doing a great job of adhering to the characteristics of simple sausages. Just be sure to draw through those ellipses at the tip two full times before lifting your pen - looks like you're stopping at about 1.5 times much of the time.

Continuing onto your insect constructions, by and large you're doing a great job. Most notably, you're honestly doing a very good job of showing respect for the distinction between operating in 3D space, treating your construction as something solid and tanigble, and operating in 2D space, treating it like a drawing, a collection of lines and shapes on a flat page. To distinguish between them is to ultimately always focus on the former - of always engaging with this thing we're creating as though it is real.

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 - rules that you generally do a good job of respecting and following, though you may not realize that you are.

For example - once you've put a form down on the page, do not attempt to alter its silhouette. 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.

I was pretty hard pressed to find a case where you were actually breaking this "rule" all that much. There are definitely cases where you'll extend the silhouette of a form out, or attempt to add to it, but when it comes to cutting into those silhouettes as shown in the diagram above, I could only find little traces of it. If you take a look at this beetle, I highlighted in red where you cut into the silhouette of existing forms, and in blue where you use one-off lines to take an existing form's silhouette and extend it out.

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. The shrimp and lobster demos from the informal demos page demonstrate this quite well too, though all said and done you're very close to operating this way already. I largely felt that explaining it in more direct terms will take what you already do instinctually, and help solidify it.

That said, I do think we should talk a bit about leg construction. Overall you're doing a pretty good job in most cases of sticking to the use of the sausage method, as explained here. There are a few places where you deviate from it, but by and large you respect the idea that it's not about capturing the legs precisely as they are - it is about laying in a base structure or armature that captures both the solidity and the gestural flow of a limb in equal measure, where the majority of other techniques lean too far to one side, either looking solid and stiff or gestural but flat.

When it comes to building on top of that simple structure, you seem to have largely stuck to the approach shown in the wasp demo, there are approaches that are more effective that I've identified in the time since producing that demo. That's certainly not pointing out a mistake - you used the resources that were available to you, as one would expect. But I do want to share some approaches that'll continue to help you yield better results, especially as you move into the next lesson.

As shown here, rather than engulfing an existing sausage in a larger form (which is similar to just redrawing its silhouette, though arguably if you're defining where it connects to the existing structure, it's still kosher), breaking up our additions into separate pieces gives their silhouettes far more contact with the existing structure, thus strengthening the bond. The key comes down to designing that additional mass such that it wraps around the existing structure. Here are some further examples of this, along with a couple examples of this in action on actual legs: in an ant's leg, and even here in the context of a dog's leg (because this technique is still to be used throughout the next lesson as well).

Now, as a whole, you've still really knocked it out of the park with this one. So, keep the points I've raised here in mind, but go ahead and consider this lesson complete.