Starting with your organic intersections, the forms themselves are drawn well, generally taking into consideration how they all sit in a believable pile, and how gravity weighs down on them, causing them to slump and sag over top of whatever forms they sit upon. When it comes to your cast shadows however, there are a few issues:

• Keep in mind that your cast shadows must abide by a consistent light source - meaning you can cast your shadows to one side, or the other, but not both.

• Whether you decide to go with really heavy shadows (like the first page) or relatively small shadows (the second page), make sure you ensure all your forms cast shadows consistently. Obviously this can be somewhat challenging when you have a ton of sausages at play as you do here, but you do still tend to have areas where a sausage should be casting a shadow, but isn't.

Moving onto your animal constructions, I can definitely see that you're making a concerted effort to apply the points raised in the lesson, although you are having some difficulty with a number of points. Hopefully I can clarify them for you.

• Jumping right in with your use of additional masses, it's really important that any form we introduce to a construction be drawn as a completely closed silhouette. As shown here, you are at least at times drawing partial shapes that are not fully closed. This makes it impossible to properly define how those new forms relate to the existing structure in 3D space.

• I also noted on that page that you've attempted to use contour lines to add volume (which became necessary because without a closed silhouette, you're not able to make that form feel solid and 3D purely based on its defined spatial relationships, so reaching for this other tool became necessary. Keep in mind however that contour lines are not the correct solution here, as they only serve to make a form feel 3D on its own, not in relation to other forms that may exist alongside it. Purposely crafting the specific shape of your silhouette is therefore critical when it comes to building up additional masses, which are all about defining clear spatial relationships.

• As you can see here, we can create forms that feel entirely solid and voluminous even without the additional contour lines, if we simply ensure that the additional masses are fully closed, and that their silhouettes are designed in such a way that they "wrap" around the existing structure, creating a believable three dimensional relationship.

• In that same page from the previous point, I also called out where you were drawing your bear's paws with way too much complexity - remember that construction is all about starting simple and building up. In this case, the bear's paws are easily broken down into a series of boxy forms - one for the main paw, and another for each of the toes. You need to always be consciously making the choice of breaking things down into simpler structures, to the best of your ability. Sometimes we get sloppy - either when we're tired, or simply tired of working on a given drawing. When that happens, take a break, or pick up the drawing again the next day.

• Also in the same page, I pointed out that you should be applying the head construction approach from the informal demos page. This lesson contains a few different approaches for head construction, and that one is the most recent, and therefore incorporates the most solid explanation I've got currently. It'll eventually be incorporated into the lesson material more directly, but until I actually have the time to do that, it has to sit in the informal demos page - although the tiger head demo page also emphasizes it. The other approaches aren't useless, just not as well refined, so they remain as well until those changes can be pushed in a more significant fashion. Now, all that said, I don't think you're applying any of the head construction approaches in this drawing - or at least, not entirely. You're kind of considering how the boxy muzzle connects to the cranial ball, so that's good, but you've only drawn circles for the eyes, and no additional structure. Furthermore, where the other head construction approaches do all stress the idea of having all the different "pieces" of the head structure (eye sockets, muzzle, etc.) wedge together like pieces of a puzzle, I'm not seeing that here. Be sure to review that informal demo and try to apply it as directly as you can to your future animal head constructions. In all fairness, you do a better job of this in other drawings, but still, be sure to go through the informal demo.

• I am definitely seeing a lot of time being invested in details - that isn't inherently a problem, or a mistake, as long as you're building up your constructions properly first, but I do still want to provide a friendly reminder that details are not the goal here, nor is creating a nice drawing in the end. Every drawing we do here is an exercise - we pick a reference image to establish a goal or a direction in which we want to work, and then we apply the exact same principles as always - start simple, build up through the addition of new forms, each time defining how they either intersect with one another (with contour lines) or how they wrap around one another (through the design of the silhouette). It's a 3D spatial puzzle, and the whole exercise in how we have to continually think through these imaginary 3D relationships, despite working strictly on a flat, 2D piece of paper.

• Now all that said, it is worth pointing out the fact that while structurally there's a lot of good about this zebra, you appear to have drawn the underlying construction (or at least the initial head/ribcage/pelvis) masses quite faintly. In the future, be sure to draw these masses as confidently as anything else. Your later phases of construction should not be darker/thicker - every step introduces 3D forms to the scene, and when you draw the earlier steps more faintly, it encourages us to treat it as just being a sketch - something less solid, less important.

• If we jump back to my notes on your bear drawing, I pointed out one spot where you seemed to kind of wrap one of your additional masses around the pelvic mass. There I called out how the pelvis and ribcage both exist inside the torso (and get swallowed up into the torso sausage), leaving no physically protruding form for masses to wrap around. To that point, all we have is the torso sausage. Similarly, on this drawing you've got that large back mass that seems to wrap around the ribcage and pelvis. This may be causing the overall impression that you've added an open form (rather than a closed silhouette). Here I can see some signs that you did try to draw a more closed off silhouette, but since it's right up against the ribcage and pelvis, it becomes visually confusing.

• I noticed that on this shark you got a little carried away with trying to capture local/surface colour, both for the greyish skin, and the black eye. Given the limited tools we're working with in this course, and the fact that as a result our drawings are all strictly black and white, local/surface colour simply isn't something we're going to capture, so you may as well ignore it altogether. In general, reserve those filled areas of solid black (like what you used for the eye) for cast shadows only, as that'll help achieve a more consistent, clearer image for the viewer to interpret.

So! I'm going to assign some additional revisions below for you to address the points I've raised here.