Starting with your organic intersections, these are fairly well done, in terms of understanding how these forms interact with one another, how they slump and sag and generally suggest the effects of gravity. These are important principles that come into play with the additional masses used in this lesson, and in several ways that does show through there as well.

Moving onto your animal drawings, I think that for the first several drawings, you struggled a great deal with observing your references carefully, and ended up with really widely varying. For the most part, I'm going to skip a number of those earlier drawings, and focus more on where you actually end up picking up steam. Before we do that however, I do want to mention a couple things about your birds.

• Your eagle actually has a stronger sense of form and construction than some of the animals that follow it, mainly in the core of its body, its head and its legs, so I don't want to lump it in as one of the "weaker drawings at the beginning"

• When drawing wings, don't try and focus too much on creating a skeleton for it. We're focusing entirely on the forms that are present, not the underlying structures we can't really see. Here's how to think of it (in rough terms).

Now, jumping down to this horse, we start actually getting somewhere. Looking at the legs there are still some observational issues - looking at the legs for example, the stance especially for the front legs is quite different in your drawing. Still, this kind of issue isn't at all abnormal, it's a matter of how much we're trying to juggle all at once. One common trick (although it takes getting used to as well) is to focus on the 'negative space' shapes between your forms. For example, the shape highlighted here in red between your horse's legs. Staying aware of the general nature of that shape between the legs will help you position those legs a little better. It's less about all the little complexities of the shape, and more what it implies about each leg's own orientation.

Moving on, while on this first horse you generally did a pretty fantastic job with the additional forms wrapping around the underlying structure, there are other drawings where it was not leveraged quite as effectively. Take a look at these additional notes - they explain a few important concepts.

The most critical thing to remember is that these additional masses are, at their rawest form, blobs. Blobs are simple, 3D things, and don't have sharp corners - they're only ever rounded. Once we push one of these blobs up against another form however, it's going to start to gain complexity where it's making that contact. It's going to wrap around that other form, in a way that may start causing more defined corners, more concave curvature, etc. But on the sides where it is not touching anything, it will remain simple.

Another important consideration is the fact that the blob itself has volume and thickness to it - you can't just deflate/inflate it at a whim - as you add it to an existing structure, it's going to add thickness to that structure. Looking at the first horse you did this pretty well, but if we look along the back of the second one, those forms feel flatter and less solid, because they're not actually maintaining their own thickness.

Continuing onto this goat, you end up falling into a pattern of treating them less like voluminous blobs, or slabs of meat (also another good way to visualize these masses), they start to look more like paper that's being wrapped around the form. No actual volume or anything, just empty, insolid structure with sharp corners that don't actually push up against anything else.

While I think that first horse had a lot of promise, overall there's a lot of work to be done in your use of those additional masses, and in applying more patient, careful observation to identify the specific forms you're drawing, and how they accurately reflect your actual reference image.

In case you haven't already, I'd like you to take a look at the informal demos page, as there are ample additional demonstrations showing how to use these kinds of concepts, along with some others. Once you've had a chance to digest that, I'd like you to do 5 additional pages of animal drawings, adhering to these following restrictions:

• Don't include any contour lines that run along the surface of a single form. I noticed you adding these to your additional masses a lot. With additional masses, we want to focus most of all on how their silhouettes wrap around the structure beneath them. You are still encouraged to include the kind of contour line that defines a relationship between multiple forms (like intersection lines, the kind that we use as part of the sausage method at the joints between sausages).

• Really spend a lot more time studying your reference image - and don't just do it up front, do it almost constantly. Only look away long enough to define a specific form as part of your construction, before looking back at your reference.

• Don't do more than one animal drawing in a given sitting, and if you feel that doing it with proper patience and care requires you to spread it out over multiple sittings, that is totally fine. The focus is on taking as much time as you need, and not rushing through any of it because of an artificial expectation of being finished by the time you get up.