Hello! Overall you've done a good job:

A general thing is that you are drawing in a small notebook I think. Try drawing on standalone A4 copy paper pages, so you have enough room to draw and the pages don't curve. It'll make it easier.

Starting with the normal cylinders you're in generall alligning the ellipses well with the minor axis, drawing confident lines and have a good variety on them, the only thing is that I think sometimes you don't take into the accoutn the degree of foreshortening when deciding the degrees of the ellipses. If a cylinder foreshortens a lot, then that means that the gap of the degrees between the ellipse closest to us and the one farther away from us will be bigger.

Here for example the cylinder has shallow foreshortening, so normally it'd have a pretty shallow change. The ellipse farther away from us would have more degrees than the closest to us, but not as much.

Now in the boxes I have a few things I want to comment on:

1.I'm not sure what's happening on some of the pages. For example here it seems like the ellipses are drawn with a different pen to the boxes, or that your pen is dying. So try changing it if you can, because it's pretty hard to tell what happens when the pen is dying because I can't almost see the lines

2.Top left box here you've extended the lines on the opposite direction.

When applying the line extension method, lines have to be extended away from the viewer.

A way to make sure you do this correctly 100% of the times, is to always extend the lines away from the center dot of the Y, as shown here:

3.Sometimes your boxes have clear divergences, I think it might just be a slip cuz you normally have them converge, but pointing it out just in case. Try to be careful about it

4.In general you seem to have trouble with alligning lines to the vanshing points, make sure you always think what you're doing wrong and why. Here for example if you extend your lines farther you'll realize where you made the mistake.

To fix it you could have done it like this In general try always to analyze what you're doing wrong, and think what could you have done to improve it. Always focus on that. It's easy to get distracted by the number (250 cylinders) and lose track of the actual goal which is the problem of these challenges. 10 cylinders thinking a lot about what you are doing and doing your best trying to figure out ur mistakes and thinking about how to fix them is gonna make you improve more than drawing 500 cylinders without thinking.

5.I think in some boxes you're getting tricked by the squares of the boxes and not alligning the ellipse to the minor axis. The ellipse always has to be alligned on the minor axis. So make sure you always draw keeping that in mind. Whenever you draw it ghost assuming you're gonna allign it to the minor axis. You can change the size, you can change the position or the degrees, but you can't change the minor axis. Here's an example.

If you look at the image you'll see that the ellipse I drew doesn't fit the square. But that's alright. That happened because the box you drew didn't have square faces. So when you draw the ellipse you need to commit to that mistake and then try to make the square on the next box. Here's how the box would have been closer to a square. So in general always allign the ellipses, if you can't make the ellipse fit perfectly it's because the box you drew doesn't have square faces, so try to figure out what mistakes you had that made the box not have squares.

To sum it up, in general you've done a good job, but make sure you focus on correcting the foundational mistakes ur boxes have (the clear divergences and the divergences in general). Make sure you always think what you did wrong when you draw a box; don't just extend the lines, think about what does that mean and how could you have improved that box. If you don't know what's wrong with your box and can't figure it out, then ask for help. But don't keep going if you don't understand.

Apart from that keep in mind the thing I said about alligning ellipses always to the minor axis, as it's super important so you both can the cylinders well, and so you learn to freehand cubes in perspective.

That's all, good job and good luck on lesson 6!