Nice work! Throughout a lot of your drawings here, you're definitely demonstrating a strong grasp of how the animals are built up through solid, three dimensional forms and how they come together to create a more complex result.

Starting with your organic intersections, these are really solid. You're selling the illusion that the forms are interacting with one another in 3D space, and are doing a great job of demonstrating how the forms wrap around one another. This is critical for how we employ the additional masses in our animal constructions, and that's something you've definitely shown improvement with over the course of much of the lesson's work.

So, getting into the animal constructions, you definitely show progress through your first few pages, and once you get into your second page of bears, and your cats, you definitely hit a good stride where your constructions feel more solid. There are some issues though that stand out.

First and foremost is that you have a tendency to use a lot of contour lines. Frankly, you use them pretty well (they wrap around forms nicely), but there is an issue with contour lines in general that they tend to have diminishing returns. If you take a flat shape and add one contour line to show how that surface actually turns in 3D space, that can have a great deal of effect. If then you add another, it'll have much less effect, and a third will have even less than that. It's very easy to end up adding contour lines that contribute little to nothing, largely because we sometimes feel like that's simply what we need to be doing. It comes down to the importance of thinking about the specific job we want to accomplish with a given mark, and to determine whether the line we want to put down is the best candidate for that task.

On top of this, there are two kinds of contour lines. The ones that sit along the surface of a single form (as explored in the contour line exercise from lesson 2), and then you have the ones that actually define the relationship between two intersecting forms, like the form intersections exercise. This second kind is vastly more effective at the task at hand, simply because it establishes a link between forms such that if one form is understood to be three dimensional, then the viewer has no choice but to understand the other form in three dimensions as well.

So, if you're able to use one of these intersection contour lines, then it's far more effective than one of the simpler ones, and will do the job on its own. I think you mad excellent use of this fact when dealing with your cat's tails. You established the connection between the tail and the cat's backside - from there, as long as you maintained a consistent width on the tail, that illusion of solidity went all the way down its length without any further contour lines.

So, what do we do with our additional masses? They don't "intersect" with the other forms, so the intersection contour line is out of the question. But before we get into diving straight into the simpler contour lines, there's one other thing to keep in mind - those masses wrap around the existing structure, in exactly the same way a contour line wraps around the surface of a form. In essence, these masses are themselves contour lines made form - they wrap around and integrate themselves through their very silhouette. Fortunately, you do a good job of this before even adding those contour lines (which generally don't contribute much of their own).

There are some adjustments that can be made, however - specifically slight changes to how you draw their silhouettes that'll make the forms feel thicker on their own, without the addition of further contour lines. I've noted them here:

• Draw each form (not just your additional masses) in its entirety, so you can understand the full scope of its relationship to the rest of the structure. Forms that are allowed to just get cut off will be read as flat shapes, causing you to have to reinforce them with contour lines in order to try and salvage the situation.

• Integrate forms into one another - this means being aware of not just the particular forms you want to draw, but a lot more of what makes up the animal's body. For example, for driving their large legs, these animals usually have some pretty hefty shoulder muscles, which will fit nicely into the big bump-mass along the back of their neck, as well as anything that stretches along their back which in turn will also integrate with the big hip muscles.

• Not marked on the page, but remember that each mass added brings its own thickness to the table - don't smooth them all together. The subtle pinches we get when rising off one mass and transitioning to another are the kinds of features that actually imply musculature. If we try and smooth everything together, we just get a sort of continuous slab that doesn't give the impression of a muscular body.

One last thing I wanted to mention was that your use of the sausage technique is sometimes inconsistent. At times you'll apply it very thoroughly, meeting all of its criteria, other times you'll apply elements of it. It's really important that you apply every aspect described here, from the sausages being simple forms of two equally sized spherical ends connected by a tube of consistent width. No ends of different sizes, no ends that get stretched away from being a sphere, no midsections with pinching or swelling. Secondly, it's important you let those forms intersect nicely and to reinforce their joints with a single, concise contour line.

You clearly know how to do this quite well, but there are definitely cases where you haven't applied it as consistently. I will admit that in the elephants, you were probably looking at my elephant demo which was draw prior to the sausage technique having been pinned down. Ultimately, while some legs may not seem to match a chain of sausages, that's entirely fine - we're just constructing an armature that will convey the solidity of the forms involved, as well as the gestural flow of the whole limb. Most techniques used for drawing legs will lean towards one or the other, but won't accomplish both as successfully. Once established, you can then add further masses as needed to bulk things out, as shown here.

So, I've laid out a great deal here, and want to give you the chance to process and absorb it. You are largely doing a good job, but I'd like to see you demonstrate your understanding of these points, so I'll assign a few extra pages below.

Oh, and to answer your question - doing a quick thumbnail sketch to get a better grasp of your subject matter is fine. In later lessons, we'll actually get into doing proportional studies of that sort before digging into the main drawing.