Starting with the organic intersections, these are pretty well done, in that you're doing a good job of stacking the forms in a way that establishes their relationships in 3D space. My only concern with it is pretty minor, but basically they lack a sense of stability - as though any moment the pile will come crashing down. Something you can do to help with that is to place more of the forms perpendicularly to one another, so they can wrap around the one beneath them.

Moving onto your animal constructions, there's a mixture of strong points and weaker points. I'm noticing that overall you're doing a pretty good job of employing the sausage method to construct the legs of your animals, and you push them a little further to add a little more complexity to those structures. One thing to keep in mind however that everything you add to your drawings must be a three dimensional form. It can be very tempting at times to just extend the silhouette of a form with a couple lines, but this causes us to interact with the construction in two dimensions - and therefore the result reminds the viewer that they're looking at a flat, two dimensional drawing.

In most cases you avoided this, but there were a few - for example the back leg of this deer, as well as towards the front of its torso. I've marked them out here.

Construction is all about building on top of the existing structure in a manner that establishes a clear relationship between the forms that exist, and the form you're adding. It also means that every component we add brings something of itself to the construction. That is to say that when we add a new form to a construction, we have to actually contend with it - it brings its own volume, its own thickness, etc. We may often want to flatten those forms out so they can smoothly bridge between forms, but it's the pinching we get when two volumes intersect imperfectly that create the nuance we see along animals' body that gives the impression of muscles beneath the skin.

To that point, looking at the back of this deer](https://i.imgur.com/C67ND8Z.jpg), you've added a little additional form but it reads as being very flat - more like a piece of paper that's been wrapped around the torso rather than something with its own thickness and volume. Compare that to the diagram here where you can see how the forms are more like solid slabs of meat - a little flexible, but still quite dense.

When it comes to head constructions, I think you've got varying levels of success, but you do have a number of tendencies that I'd like to correct. Biggest of all is the tendency to have your eyesocket float more loosely on the construction. Instead, if you look at the head construction demos at the top of the informal demos page you'll see how important it is to treat the various elements of the head (the eye socket, muzzle, brow ridge, cheek bone, etc.) as the pieces of a three dimensional puzzle. Instead of floating loosely and independently, they should all fit together, with each component buttressing the eye socket.

The last thing I wanted to point out has to do with your tendency to draw much of your construction more lightly as a sort of under-drawing, then to go back over your lines with a darker stroke to replace a good deal of the lines you want to keep. There are two reasons this is not an approach I'd like you to use at all in these lessons:

1. We need to respect every single mark we put down, and every single form that adds to the scene as though it is truly adding something solid and real. If you have it in your mind that these forms are just an underdrawing, that they're not really there, then you're not going to really treat them and the way they interact with one another in a fully realistic fashion. This is how you end up with those places where you just extended silhouettes rather than actually building up more and more solid, three dimensional forms.

2. When going back over your linework in this manner, one has a tendency to "trace" that linework - this basically means following the lines as they exist in the two dimensions of the page. It makes it very easy to forget about how the lines actually move through the world as three dimensional edges, and in turn we end up missing certain subtleties that can flatten out our work.

I've laid out a number of things here that I'd like you to focus on, so I'm going to assign a few more pages to help you demonstrate your grasp of those. Before that, I'd also like you to follow along with some of the informal demonstrations from the end of the lesson. I'll list the specific assignment below.