You've definitely shown a fair bit of improvement from the first 50 to the last. Towards the beginning you were definitely struggling with cases where a given set of parallel lines would diverge as it moved away from the viewer - an obvious break from the principles of perspective. As you progressed through the challenge, the frequency with which this occurred dropped off pretty quickly, showing that your grasp of 3D space was improving quite a bit.

While you have shown definite improvement over the course of this challenge, there are still some areas where you have gotten better, but still have ample room for growth.

The first thing that jumps out at me is your line quality. This is much more prominent in the larger boxes (honestly I think towards the end there you were drawing a lot of full-page boxes that were pushing your skills a bit too far - hitting your limits is definitely important, but it's definitely possible to challenge yourself so much that it gets in the way of actually learning from the process). The main thing here is that your lines are still being drawn somewhat more slowly and hesitantly, instead of applying all three stages of the ghosting method properly.

Remember that the ghosting method is all about separating the process of mark making into three distinct phases. First we identify the specific job we want our line to accomplish, marking out the start/end points and assessing exactly how that line ought to behave. This can involve thinking about how it needs to align towards a vanishing point it might share with other lines (that may or may not have already been drawn), for example. During this phase, we'll also want to think about how our lines leave that vanishing point, as shown here. After all, if you do have other lines within a set already drawn, you can think about just how big of an angle there actually is between them at the vanishing point. If that angle is very small, we can usually get away with drawing our line very close to parallel with the other.

The second phase of the ghosting method is preparing - ghosting through the motion in order to communicate the marching orders to our arm muscles. This is where the brain sorts out how to accomplish the task determined from the previous step, and is the last point where our brain will have direct control, gradually yielding more and more as our arm muscles get a sense of the motion we need to follow.

Lastly, the execution is entirely the muscles' responsibility. Our brain does not interfere, does not attempt to steer as we draw, and we no longer think about anything involving accuracy. Any opportunity to avoid a mistake has passed - all we can do is push through without hesitation and focus on keeping our line smooth and our trajectory consistent. If our line wobbles, that means we were not drawing confidently, and that our brain was interfering.

Students often struggle with this because they get caught up so much in accuracy being their main focus. Accuracy is nothing if your lines aren't smooth - a smooth line that misses its mark is still more valuable than a slow, belaboured, wobbly stroke that follows its path (though veering this way and that).

Stepping back to the first phase of the ghosting method - planning - we come to the last issue I wanted to point out with your boxes. When drawing your lines, it's critical to always focus on how your lines converge to a vanishing point. Even if you haven't drawn some lines of a given set, you still need to think about where they would be. Often students will get distracted by other elements of the box - often thinking about their back corner, as this is usually where we see the biggest discrepancies - but these are all distractions. Whenever you're drawing a line, all you need to hold in your mind are the line you're looking to draw, and the other 3 lines that run parallel to it. Think about how they converge towards that vanishing point consistently, and how they need to be oriented in order to achieve this.

It's very common for students to think about just two lines at a time (like on box 250), causing them to align in pairs (usually pairs that share a plane). In the case of box 248, it seems that you've thought specifically about keeping those lines parallel on the page instead of the idea that they would eventually converge. Even if that vanishing point is infinitely far away, you still need to be aware of it - always focus on those convergences, on those 4 lines that share a vanishing point, and nothing else. Even if you're finding that the back corner of your box gets messed up, it is just a symptom - the solution is always at the vanishing points, not the back corner.

Anyway! All in all, you're moving forward, and you've completed this challenge successfully. I'll go ahead and mark it as such.