Most of these are quite well done! Though I did notice that for your freehand ones, I could be wrong on this but it does look like you drew underneath with a pencil or something faint, then tried to trace over them. As a result, you traced over them more slowly and hesitantly, focusing more on how those lines run along the page in two dimensions rather than how they exist in 3D space. They ended up coming out less evenly shaped than they should, and the forms themselves weren't as solid and three dimensional. Keep in mind that while I allow the use of ballpoint pens, ellipse guides, etc. at this point, that doesn't mean it's a free-for-all on what kinds of tools you can use. Pencils, and tracing back over your work in general, is still not allowed, and it will have a negative impact on your work.

Once you hit 12, the kind of confidence I want to see comes back into play, so this is undoubtedly where you got your ellipse guide, and your results definitely improve quite a bit. One thing I am noticing is that I think you have a habit of drawing the far end of your wheels (that is, the ellipses on the end facing away from us) to be a little large - this is probably because of the limitations of your ellipse guides, so it's understandable, but it does sometimes cause our wheels to feel a little bit off in terms of perspective.

I am very happy with your tendency to focus on cast shadows when dealing with your tire treads - you're doing a great job of capturing those textures through implicit means (rather than explicit constructional techniques), and so you end up with a lot more control over how you go about conveyuing those textures. You don't end up with drawings that feel too noisy or distracting, instead you include just enough texture to convey how that surface feels, and no more than that. Well done.

One last thing I do want to mention however is that in a few places, you do tend to try and capture the form shading of your wheels, usually by using hatching lines. As discussed back in lesson 2, we don't worry about form shading in this course. There are ways form shading can be used as an excuse to capture finer textures, but we don't ever include form shading just as decoration.

So, with that, I'll go ahead and mark this challenge as complete. Just remember as you move forwards that you should not be laying down any loose or light sketches, then tracing on top for any of these lessons.