Starting with your organic forms with contour lines, while these are for the most part moving in the right direction, I did notice a few points worth calling out:

• Firstly, always follow every step of the instructions - you seem to be missing out the central minor axis line that is meant to pass through the center of each sausage, giving us something more concrete to align the ellipses to.

• You appear to be placing little ellipses on both ends of each sausage form - those ellipses are no different from the contour curves themselves, except that when the tip of a sausage faces the viewer, we're able to see the whole way around, so we draw a full ellipse and not just a partial curve. The key point here is that the tip of the sausage needs to be facing the viewer. You've been adding them to all the ends, whether they face the viewer or not. Remember that what you convey to the viewer about the form's orientation using the contour ellipses needs to be consistent with what the contour curves themselves are saying. In this example you can see some examples of different configurations - one with both ends facing the viewer (resulting in an ellipse on each end), one with neither end facing the viewer (no ellipses) and one with one end facing the viewer (one ellipse). It's important that you understand what every mark you put down is meant to convey.

• Also, don't forget to draw through those ellipses as well, as you should for all the ellipses you freehand throughout this course.

Continuing onto your insect constructions, as a whole I do think you're applying many of the core principles of construction quite well. The way in which you're approaching drawing these creatures suggests in many areas that you understand how the things you're drawing exist in 3D space, how they fit together, and how they combine to create more complex results. That said, you very much have a tendency to jump back and forth between acknowledging some components' three dimensional, solid nature, and treating others more as being rougher sketches/explorations on the page to be ultimately ignored or discarded.

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.

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.

A pretty significant example of this is how in this lobster drawing you started with a larger sausage form, then went on to create another smaller structure inside of it, ignoring the initial one altogether.

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. You can also see this in practice with the lobster demo you were following - at no point do I second-guess or revise any structure I've already drawn. Once a form is laid down on the page, it is treated as though it is solid, and real, because that is how the viewer will interpret it. There's no way to communicate otherwise, because the viewer is not processing the drawing with their conscious mind - they're letting a lower level of consciousness to very quickly process that information and glean what they need to from it. If they have to engage their conscious mind to make sense of something, then you've already lost their suspension of disbelief.

This is all part of accepting that everything we draw is 3D, and therefore needs to be treated as such in order for the viewer to believe in that lie.

While there are plenty of more obvious examples of this in your work, keep in mind that it can occur in some smaller, less expected scenarios as well. For example, here in the louse demo drawing, you similarly cut into the silhouette of existing forms when adding segmentation, when instead that segmentation should have wrapped around the existing structure, adding to its volume/thickness.

Now it's inevitable that there will be plenty of cases where we follow along with our reference image, and find that the mark we put down established a form that was too big, or otherwise inaccurate. This is completely normal, but you should not be attempting to correct the given mistake. Our goal in these drawings is not to reproduce the reference image at all costs - rather, each drawing is just an exercise in spatial reasoning, a 3D spatial puzzle to solve, and the reference image is just a source of information to help us build up something solid and tangible on the page. Through solving these puzzles over and over, our brains are gradually rewired to better understand how the things we draw on a flat piece of paper exist in a three dimensional world - but only as long as we continually and consciously reinforce that idea for ourselves.

One last point I noticed 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, in 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.

Now, I am going to mark this lesson as complete - these certainly are significant issues that I've called out, but you should be entirely capable to address them throughout the next lesson's material.