Howdy, TA qzhans here!

First, superimposed lines. Overall, nice work here; I’m not seeing a lot of fraying at the starts of the lines here, and I like your confidence as well (despite some expected arcing).

Moving onto ghosted lines, that confidence continues. I’m liking the variety here too. The next step up for these would be to continue to increase your accuracy, which will develop naturally over time.

Your ghosted planes are a marked improvement in your linework skills. Very confident, accurate linework here. Nice.

Moving onto your ellipse tables, I like that you're keeping your ellipses tightly packed within the bounds that you've set. There's expected room for improvement in getting your ellipses to be tight and tidy, but drawing through with confidence is more important at this stage, which you mostly are; there was a little bitt of wobbliness at the start that seemed to have gotten ironed out throughout the attempts.

Your ellipses in planes are good as well. You also don’t stretch out your ellipses needlessly to hit the bounds, opting instead for a confident ellipse. The next step for your ellipses would be improving your ghosting technique even further, so that you can reliably tuck in that tail end every time.

Next, your funnels generally do a good job of aligning to the minor axis that you've set. The only caution I can give are the funky ones you attached onto the side of one of your funnels, left of the center of the page. This exercise is really about getting used to the use of the minor axis line, so a variation like this where a minor axis line isn’t present defeats the purpose of the exercise.

No problems with plotted perspective!

For your rough perspective, I’m pleased to see that you are applying the error checking method correctly, extending your lines parallelly back to the horizon line instead of directly to the vanishing point. I do see a few issues with keeping the verticals perpendicular to the horizon line and the horizontals parallel to it, so watch out for that. Additionally, a problem I want you to pay attention to is a little bit of degradation in your line work, with an extra line here and there, perhaps to correct some perceived mistake. Remember that all lines we put down are law, and laying down more lines to fix something will only create more contradictions and draw eyes to a mistake.

And now, the one you’ve been waiting for: rotated boxes. Before anything, I wanted to congratulate you on its completion; it's not something you're really supposed to be ready for. In general, I like how you’ve structured this exercise, keeping the gaps between boxes consistent between each box. Tip: you can apply this same idea to the back faces too. In the same way that the front faces form a half-sphere of faces divided by equal gaps, the back should form its own half sphere. That would’ve helped you figure out some of the tricker boxes towards the edges. In terms of drawing through your boxes, this is a pretty good attempt. You did miss a few, but overall I can see that the thinking is there. As a result, the illusion of rotation here is quite solid, as you’ve gotten the shrinking and turning of the faces on the outer boxes down pat. The issue here seems to be your linework again, which may have gotten a little patchy/sketchy due to the difficulty of the exercise.

Finally, onto organic perspective. In general, your boxes do a good job of shrinking and growing as they move through space. I'm pleased to see a little bit of overlapping here and there as well (although I do think you could've done a bit more). There's work to be done in getting those parallel lines to converge to their shared vanishing point, but you can iron that out with the box challenge. You actually don’t have to draw through any of the boxes in this exercise, but I guess it doesn’t hurt. You’ll be doing a lot of this in the 250 box challenge, so I hope you liked it! The issue here again would be linework. There is a tendency to get very sketchy in places, patching up or re-drawing lines. Give every line your best attempt, and if you screw up, play around it instead of drawing even more attention to it with fixes.

Overall, there’s a lot of good effort and understanding being applied in this lesson. I’m tempted to just wave you onto the lesson on that alone, but I think the box challenge will be hell for you if you don’t get this linework habit worked out. Thus, I’d like to see one more page of organic perspective from you (don’t draw through this time), focusing on resisting the urge to re-draw or patch up any of your lines.

P.s. in regards to your AB box question. Personally, the box you've drawn, despite having a convergence error you can measure if you take a ruler to it, looks quite solid to me. I could give you a technical explanation about what you should do here, but I really don't think it'd be useful, and is something that you will eventually be able to solve once you get more experience. Plus, the margin of error for the illusion to work is quite large. I'd caution against stressing over every box like this, because this internal understanding of perspective is a lot like language in that, just like a native speaker intuitively knows what's gramatically correct over a lot of time with the language, you too will know what is intuitively correct in perspective the longer you do it. The 250 box challenge is designed with that in mind, so don't be hung up if you don't "get" things... it will come in time.