Oh wow, I kind of hate you for making me look at a centipede. I can handle spiders mostly, and the majority of insects are unpleasant but okay, but... that centipede, jeez.

Anyway! You did start up with a small hiccup in that you missed one of the steps of the organic forms with contour curves, which is usually a big red flag, but I was pleasantly surprised that your insect constructions actually demonstrate a fairly thorough understanding of construction and how these kinds of spatial problems ought to be approached.

The thing you're missing in your organic forms with contour lines is the central minor axis line which helps us to better align the contour lines (whether they're ellipses or curves) to the general flow of the form itself. Make sure that you regularly go back to review the instructions of these exercises - especially when they're assigned as part of a lesson - to avoid moving forward without following them expressly as they're written.

As a side note, there are a couple other things to keep in mind when doing this exercise:

• Make sure you're sticking to the characteristics of simple sausages, as explained here. You're not too far off, and you are definitely trying to keep things simple, but you do often end up with ends that aren't entirely circular (sometimes they're smushed or stretched out), or midsections that get much wider instead of maintaining a consistent width.

• You seem to be keeping the degree of your contour lines roughly the same throughout the length of a given sausage. As explained in the lesson 1 ellipses video, these cross-sections will gradually get wider as we slide away from the viewer.

Moving onto your insect constructions, what I am most pleased to see is that you are putting a lot of effort towards building up your constructions through the addition of individual, enclosed, solid, three dimensional forms. A lot of students at this point will still be caught up jumping between working in 3D (as you are) and working in 2D (that is, allowing themselves to draw individual lines, or partial shapes with no clear relationship defined with the existing structure in 3D space).

Even the area I would have expected you to switch back to working in 2D - that is, when adding tiny spikes on your mantis' arms - you were still drawing many (though not all) of them as fully enclosed forms. In this, there's only one change I'd make - make sure that the part of the spike's silhouette that actually makes contact with the existing arm structure curves inwards to wrap around the form, as shown here.

Now, there are a couple of things I do want to call out.

• I can see that you're definitely making a strong attempt to employ the sausage method. This is good - it's an important technique that will be useful both in this lesson, and in the next one, and helps us to establish a solid base structure from which to build up our legs. In the diagram I just linked, however, I do want to stress the fact that it says you should be adding contour lines only at the joints, to define their relationship with one another, and not through the length of a given sausage. You tend to do this on occasion, and those contour lines aren't really contributing anything. The solidity and 3D nature of that segment comes entirely from the relationship being defined between it and the other forms to which it connects.

• Once you've got your sausage structures in place, you push even further and build upon those structures. That's fantastic - it shows that you understand the sausage structure's role as a base armature, rather than trying to capture everything pertaining to the leg all in one go. There are however better ways to build upon the structure, as shown here and here. Note specifically how instead of engulfing the entire segment in one big mass, we break it up into separate masses that wrap around individually. This allows each mass' silhouette to make more contact with the sausage structure, defining a clearer relationship with it, and making everything feel more solid. You can see this at play in this ant leg and in this dog leg (since as I mentioned, we'll be using this technique throughout the next lesson too).

• This is actually a bigger concern for most students, but I barely saw it in yours. Still, since it did come up, I figured it'd be a mistake not to address it. In this wasp's head (and in the little thorax drawing on the left side), you started with a lighter exploratory ellipse, effectively defining a ball form, but then you cut back into that silhouette to make it smaller. As explained here, cutting back into or modifying the silhouette of your forms should be avoided entirely. Once a form is established, continue moving forwards as though it's as solid as a chunk of marble. Avoid treating your construction like it really is just a drawing on a flat page - doing so will communicate that fact to the viewer, and that will undermine their belief in your illusion.

Aside from that, you've done a really good job here. In regards to your approach with the centipede, you largely handled it as I would have - creating a chain of boxes like the "boxes on a string" exercise from the additional section of the box challenge. This is also the same approach I would use on snakes. What matters most is that you're working in 3D (rather than 2D), that you're starting simple and building up complexity through the addition of new, complete, enclosed 3D forms. The reason this approach is better in this case than using sausages or a branch is that both of those options result in a cylindrical structure, whereas this one more clearly separates the body into distinct planes - a top, a side, etc. This lends itself better to understanding the structure as it exists in 3D space.

So! I'll go ahead and mark this lesson as complete.