I think as a whole, you should be pretty proud of what you've achieved here. Most students have a fair bit of trouble fully digesting the concepts in this lesson, but I feel that throughout your homework submission, you've demonstrated a pretty strong grasp of the main principles I've covered both in this lesson and in those preceding it.

That's not to say there aren't a couple issues I'll address, but overall I'm very pleased with the understanding of spatial reasoning and of constructional principles we're seeing here.

To start, your work on the organic intersections is solid. You're clearly demonstrating how these forms interact with one another in 3D space, and have them resting firmly atop one another with a strong sense of gravity to them.

Moving onto your animal constructions, I'm pleased with your general respect for how every mark you put down on the page is itself a solid, three dimensional entity being added to the construction. There are a few places where, in some ways, you break this rule, but for the most part you adhere to it quite closely. Some places where you break the principle are where you don't quite draw each form in its entirety, instead allowing certain forms to stop where they intersect or are overlapped by another form. For example, the legs on the opposite side of this fox are cut off in this manner (especially the back leg). When it comes to legs, the issue there is actually more related to a larger concern that I'll address in a moment, but it is something to keep in mind. Whenever you introduce a form to your construction, make sure that you draw it in its entirety. Don't worry about what part of it would or would not be blocked from view - drawing the whole thing helps us better understand how it sits in space relative to its neighbours.

Another similar issue comes down to a few places where you're trying to do too much all at once - that is, jumping into a greater level of complexity rather than building things up from simple forms. We can see this in this horse's lower legs/hooves, as well as this frog's feet. It's not that these were drawn poorly (although some definitely flattened out for this reason) - it's more that each of these drawings serve as an exercise for developing your spatial reasoning skills, and so if you lean towards the choices that are more interested in making the drawings pretty, then that defeats their purpose.

Now, for the most part, as I mentioned before, you still respect the principles of construction a great deal, and draw most of the core forms in their entirety. I'm also pleased to see how you define the connections between different forms, such as where the neck connects to the torso.

I did mention an underlying issue with the legs of your animals. That comes down to the fact that it appears you didn't employ the sausage method that was introduced in lesson 4. This technique is still extremely effective at constructing legs, for the simple reason that the technique allows us to capture an underlying structure or armature that establishes both a sense of gesture and fluidity, as well as an impression of solidity. Other techniques tend to lean too much towards one or the other, either appearing fluid but flat, or solid but stiff.

It's true that most of the legs you see won't match a chain of simple sausages - this is why we're just building a simple armature from them first. Once in place, you can them add additional forms to your constructions to add bulk where it is needed, as shown here. Long story short, make a point of using the sausage method for all the legs you construct.

When it comes to adding additional forms, you largely do a good job, but you could stand to stress how these masses wrap around the underlying structure a little more. I've demonstrated the issues here. You have a bit of a tendency to draw the forms with less thought to how they're actually integrating into that structure - more like at times, you're placing flat shapes on top.

The last issue I wanted to point out was with this corgi. Basically, as pointed out there, in order to draw the fur around its neck, you ended up modifying it on a 2D level. Instead of adding another complete three dimensional mass that wrapped around the existing structure there, you took the silhouette of the neck and extended it out, basically taking a 2D shape on the page and changing it. This breaks the illusion that what we're looking at is 3D. To put it simply, always build things up in solid, complete, three dimensional forms. Don't interact with your drawings in two dimensions, otherwise you'll undermine the illusion you're trying to create.

I've laid out a number of individual issues, but I'm still confident that all in all you're demonstrating a good grasp of the material. As such, I'll go ahead and mark this lesson as complete.