Starting out with the organic forms with contour lines, there are a couple issues that stand out to me, and I've pointed them out here:

• Don't forget to add the contour ellipse on the tip facing the viewer. This contour line is often the most impactful in making the form feel solid and three dimensional.

• The degree of your contour lines tells us of its orientation in space, relative to the point of view of the viewer. As we slide along the length of the sausage form, the degree will get wider or narrower (narrower closer to the viewer, wider farther away). This is the default, given a roughly straight sausage - if the sausage itself turns in space, then it's taken into consideration along with that turning/bending.

• Overshooting your contour curves is extremely useful to nail down the proper curvature of the sausage's rounded surface. Because you didn't do this, you ended up with much shallower curves that didn't quite wrap around properly.

Moving onto your insect constructions, while there are a number of ways in which you're moving in the right direction, there are other concerns that are steering you astray somewhat - things we can correct to improve the overall results. You certainly are holding to the general principle of building up your constructions from individual components, and I can see improvements on this front and the resulting solidity of your drawings, so what I'll point out below should help build on what you've already got going.

The first issue that stands out is something we can see on the weevil drawing on this page, as well as the abdomen of the odonata above it. Basically when using constructional techniques, our focus is on the idea that every mark we draw defines a solid, three dimensional form in the world, and that respecting the three dimensional nature of it is paramount. Any action that treats it as anything less is avoided, because it would otherwise reinforce the truth that we're really just looking at a flat drawing.

You started out with the weevil's abdomen with a regular ball form, which is good, but then you cut across its silhouette to create that dip in the form, connecting the two spikes. This is incorrect, because the silhouette itself is a 2D element, not a three dimensional one, and therefore interacting with it reminds the viewer that they're looking at something two dimensional.

You can think of the silhouette like the footprint of an animal in the mud. You may not have seen the animal itself, but you can gather a fair bit of information about it from the footprint. What kind of animal it might be, how big it is, how quickly it was moving, etc. But if you modify this footprint, you're not changing anything about the animal itself - you're just making the footprint itself less useful as a source of information.

Cutting across the silhouette is basically an incorrect way of applying 'subtractive construction', which you can read more about here. There is a more correct approach which involves using contour lines to separate the 3D form into two separate forms and then denoting one as positive space and the other as negative space - but this is the sort of thing that is more useful in geometric construction, rather than organic. For organic, additive construction - starting smaller and building up through the use of additional forms that wrap around the existing structure is more effective. This is something we'll dig into more in the next lesson.

For the dragonfly's abdomen, you can see a more successful approach in this demo I did for another student. Note how it involves building on top of the existing structure, not cutting back into it. In the case of a leaf, or something else flat, we could ostensibly cut back into things to add edge detail - but since there is three dimensional volume here, that no longer continues to be an option.

We can see more of these issues in your amazonian beetle, but the reason I wanted to call this one out in particular was how you added that bump on its thorax with a circle. Note - it's a circle, not a sphere or some other three dimensional mass. Circles are 2D shapes, and there wasn't really much done here to understand it was a 3D form. The approach you employed here was definitely rather quick, putting down the basics that you needed to get in the general direction of your goal, but taking more time to properly respect every entity you draw as being three dimensional and grasping the actual relationships between those forms in space, will help you push your construction much farther.

Another point I noticed is that you seem to have employed a lot of different strategies for capturing the legs of your insects. It's not uncommon for students to be aware of the sausage method as introduced here, but to decide that the legs they're looking at don't actually seem to look like a chain of sausages, so they use some other strategy. The key to keep in mind here is that the sausage method is 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. Once in place, we can then build on top of this base structure with more additional forms as shown here, here, this ant 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). Just make sure you start out with the sausages, precisely as the steps are laid out in that diagram - don't throw the technique out just because it doesn't immediately look like what you're trying to construct.

One last point comes down to the contour lines you tend to add quite freely across your constructions, like in the ant on this page. Contour lines are very useful tools, but it is critical that you think and weigh their purpose and your intent in using them for each and every time they're employed. Technically that stands for every single mark you draw - while going through the planning phase of the ghosting method, ask yourself what you want to achieve with this mark, whether there are other marks that are already accomplishing that task, and what you could do to achieve that goal more effectively with the mark you're drawing now.

As I called out in your organic forms with contour lines exercise, you have a tendency to draw them such that they're quite shallow in their curvature and don't actually reinforce the illusion that we're looking at a rounded, 3D form. When combined with more complex shapes (like those used for the ant's legs) this can just reinforce the idea that we're looking at things that are flat. As a whole, note that part of the sausage form is focused around only putting contour lines right at the joint between the sausages, as these contour lines are vastly more impactful (because of how they define the relationship between multiple forms in 3D space). Outside of the sausage technique, you can use contour curves but it's important that you first deem that they are truly necessary, and secondly focus on executing them to the best of your ability. Rushing through them does you no favours.

Now, the last point I want to mention is what you mentioned yourself:

So, I know I went a little overboard with some half-assed rendering. Please forgive me if it's louder than what the exercise calls for -- which is, of course, not pretty drawings. Not that these are pretty or anything. I just sort of wanted to try and see if I could use contours here and there to suggest form and value. I'm just trying stuff.

Back in lesson 2, I mention that rendering/form shading is actually not a part of this course. While certain circumstances - like using form shading as an excuse to integrate texture are arguably okay, general use of hatching really, really should not be part of the work you do here, and it's critical that in the future you take greater care in following the instructions as they're written. We specifically don't concern ourselves with form shading here because it tends to be a big distraction from thinking more firmly about the underlying construction. I won't beat a dead horse much further on this, so just make sure you leave that experimentation for the drawings you do on your own.

I will say this though - the use of solid black shapes in your mantidfly is well done. Those filled black shapes should be reserved for cast shadows, either in terms of textural shadows or the kind used here to help some forms stand out against others.

As a whole I think you are showing a lot of overall understanding, and clear skill and capacity for this kind of thing, but you're letting yourself wander off the path that this course intends for you. While you understand the fact that the goal is not to focus on creating pretty pictures, you're still giving way to that and need to be more purposeful in your following of the instructions.

So! To let you do that, I'm going to assign a few additional pages of exercises below.