Yo Goodboy! Congratulations on finishing the challenge!

Starting with your cylinders with arbitrary minor axis, I have some good things to say about them, and also some other things so you can keep on the right track:

It looks like you've went for a pretty stiff approach on them, sticking mostly to 2 point perspectives and some pretty similar convergences. The main thing here is that this challenge is supposed to be done mainly on 3 point perspective just like the box challenge, this doesn't mean that you've done it all wrong, it just mean that you could have taken more advantage of this challenge by just trying to experiment with more odd angles and different kind of cylinders. I think that this is somehow related with your wobbly lines issue and caring too much about the end result, now I had (and still have) really similar issues where my hand would just shake for a whole 2 hour construction on my lesson 6, though you have to start to realize that not also the end result it's not the main thing here, but that this course and this lessons should be your safe spaces for you to mess up. Remember that that's the main point on this lessons, to mess up and get someone to look at that mistakes and tell you how to get over them, that's why it's not only totally fine to make mistakes, it's encouraged to fail! So, on future lessons, don't play it safe, try to experiment and see how you can play with this concepts withing the ,borders provided, remember that not only you will learn more this way, there is going to be someone to check your work later and help you out.

All this said, I think you did a pretty solid job on understanding some of the core concepts that this challenge is supposed to teach you, it looks like you are doing a good job consciously checking the minor axis of your ellipses and I can see that the margin of error of matching your ellipses minor axis with the arbitrary minor axis, got better as you progress through the challenge!

One thing that I'm glad to see is that that you've done some variety of rates of foreshortening, even with the issue we've had already talked about. This helps me to check different mistakes that people make at this stage, and indeed I found one!

This issue that I'm talking about is related to keeping your foreshortening- and the various manifestations of it- consistent. Now, when it comes to cylinders, the foreshortening is manifested in two "shifts", the first one is the shift between the closer ellipse in space which is bigger than the more further away ellipse which is smaller, and the other shift is between the degrees of this ellipses, the further one being wider than the closer one. The key point here is to make sure that there is never a dramatic shift in on of these, while there is a more minimal shift in the other.

Now lookin at your cylinder 147, we can see that the shift between sizes is pretty notable, while the shift between degrees is very subtle, now this is an example of one of the ones you did wrong just for your to understand better this concepts, but it looks like you've been unconsciously taking this into account in others! For example your 137 has a pretty close relation between shifts. Now, there are mor examples of both cases, but I'm confident that you were able to start grasping this concept on an intuitive level, so now that it is explained here I have no doubt that you will be able to maintai it on a more conscious and regular level moving forward!

Moving on to your cylinders on boxes, they do suffer from the same issue as your arbitrary cylinders, I think that you've done way better job on your 3 point perspective ones than the ones that you forced yourself to do 2 pp. This said, I think that you've done a very solid improvement on mathing your ellipses minor axis to the boxes vanishing points, this means that you are being able to create circles in 3d, if you are able to this, it also means that you are also able to create squares on 3d space, since that's the plane you need to create a circle. This was the meat of the challenge, and it's visible you've improved on it!

Lastly, covering this issue again, you are getting to the last stages of this course, don't play it safe, try to make the most of what you got in front (which is more than you would think) and I recommend that you start warming up with ghosting, lines ellipses whatever, but that was what helped me quite a lot, and also, go back and check this section on line princples, it's always good to go back and see what is it that we need to take into account with our lines.

Now, you did good on this challenge and showed that you've improved, so I'm gonna go ahead and mark it as completed! Keep up the good work.