Alrighty, let's jump right into it. I'm guessing that you decided to switch from your ellipse guide to freehanding for after your first 10 because of the obvious size limitations of the more affordable "master ellipse template" option (with a full set of ellipse guides costing an arm and a leg). I am glad that you gave the ellipse guide a fair shake.

With most students, I'd definitely encourage continued use of the ellipse guide (and even in your case, there will be ample need for it into Lesson 7, especially when we use ellipses to help create 3D unit grids to help establish the proportions of our vehicle constructions), but I will say that you've done quite well even when freehanding your ellipses. Things definitely do get a lot more loose and erratic, but you still manage to hold your wheel constructions together quite well. There are however some things you've ended up doing as a result of the general looseness of your ellipses, which I prefer students avoid in this course:

• Most notably, you definitely end up executing those larger ellipses more loosely, then tracing back over them a little more slowly with a darker, heavier stroke. Remember - as soon as you go back to freehanding, the rules of the ghosting method kick in, and you need to be executing each mark by going through its three distinct phases - planning out the ellipse you wish to execute, preparing by going through its motion and pushing it down into your muscle memory, and most importantly, executing with a confident, smooth stroke. Hesitation leads to uneven shapes and wobblier lines which, even if only present minimally, will undermine the solidity of our constructions.

• Similarly, you end up with some visual contradictions - where one mark declares the presence of one form, but another mark declares the presence of another, different form, occupying the same space. Basically the kind of thing we talked about back in the Lesson 4 critique, where I stressed the importance of not cutting back into the silhouettes of forms. Remember - what we're doing here is not sketching. We're constructing, and everything that falls upon the page does so with a purpose. Sure, mistakes happen, but we have to keep rolling with them. So for example, with this wheel clearly has a fainter ellipse in the middle that exists at a fundamentally different orientation from the rest, creating a contradiction.

• And again, pretty much part of the same issue, but the whole fainter underdrawing followed by a darker clean-up pass is an approach that should not be employed in this course, as discussed here back in lesson 2.

Of course, none of these issues are present in your first ten, and again - the work you did with your freehanded ellipses is still better than most. Many others have tried the same thing, and have had their wheel constructions fall apart as a result.

Now, my critiques of this challenge generally break down into two categories - construction and texture. I've talked about construction in part, but there is one other thing I wanted to call out, which is present across the whole set. One thing that really helps us achieve a stronger sense of "inflation" for the tire itself is having smaller ellipses towards the outside, and larger ones towards the middle, or at least some kind of beveling at the ends. That is, as opposed to just drawing basic cylinders, with a midsection that maintains the same size as the ends.

There are some instances where you made the midsection a little bigger, especially earlier in the set (when you were working with your ellipse guides) - for example, this one. This definitely made a difference in the impression of the structure, whereas those that stuck to a consistent diameter throughout felt more stiff and solid. Note that this is something I talk about here.

Continuing onto the other side of this challenge - texture. In all honesty, I assign this challenge at this stage in the course in part as a bit of a trap. Many students are far enough detached from Lesson 2's texture section that they forget its principles (and perhaps forget to review them), and as a result they fall back to things like explicit markmaking, and don't rely as much on purposefully designing shadow shapes as they should.

In your case, I don't think this is true. I can see plenty of individual examples - to varying degrees - where you do indeed think about employing implicit markmaking techniques, and where you leverage cast shadows. For example, this one. While you definitely didn't take the additional step of first outlining your intended shadow shapes first (which makes it much easier to design them in a purposeful fashion), you did clearly draw shadow shapes. Just remember - in this course, when we grab a brush pen or a thicker pen, it's to fill in a shape that's been drawn, not to "paint" right on the surface. All the important stuff is always done with the main pen - be it a 0.5mm fineliner like throughout most of the course, or a ballpoint pen as is allowed here.

Now, there are other cases where you come close to this, but miss the mark a little. If we look at the texture on the tread here, I'd say you're pretty close (and honestly the result comes out quite nicely, and I quite like how towards the center, different tread forms blend into one another), but there is an aspect of muddiness to it where it's unclear whether you're trying to draw the shadows those textural forms cast, or whether you're actually filling in the side planes of each textural form - basically the distinction made in this diagram.

So, I'd say that while you're demonstrating enough here to show an awareness of the general way we ought to be thinking about texture, there is some room for refinement in your approach.

Anyway! As a whole, I'm still very pleased with your results, and while I've been particularly nitpicky and critical here, you're still doing very well. As it stands, you're doing a good job compared to the majority in using your freehand ellipses here, but I still wouldn't rely on them for Lesson 7 unless absolutely necessary. It's just such a demanding lesson that being able to let your ellipse guide do the heavy lifting really makes a difference.

I'll go ahead and mark this challenge as complete.