2:36 AM, Thursday September 9th 2021
Starting with your form intersections, these are looking pretty good - specifically in regards to your intersections, which demonstrate a well developing grasp of the manner in which these forms relate to one another in space. There are some spots where your linework gets a little hesitant, mostly where you seem to go back over whole lines with additional line weight. I'm not sure if this is a case of the line weight itself making the lines wobble (hesitantly tracing over lines rather than adding weight with the ghosting method, with the same confidence we'd use for any other mark, is a common cause of this), or if you're adding line weight in those areas in an attempt to fix things. If it's the latter, then don't - line weight is a tool that serves a specific purpose, and it shouldn't be leveraged to try and hide mistakes. Mistakes happen - every drawing we do in this course is just an exercise anyway, rather than a performance. If it's the former, remember that line weight is something we add to help clarify overlaps that occur between forms in specific, localized areas. Focus the line weight where those overlaps occur, as shown here.
Aside from that though, the other lines are drawn quite confidently and clearly show a good use of the ghosting method.
Similarly, your cylinders in boxes are coming along well - I can see that you're going through the error analysis correctly. For this exercise though, I might set the ellipse guide aside, just so you can ensure that the line extensions are being done with ellipses that fit within the given planes more accurately (since you were definitely forced to pick the "best fit" out of whatever your ellipse guide offered, sometimes leading to some significant gaps).
Now, moving onto your vehicle constructions... your work here is phenomenal. I honestly have no complaints whatsoever. You've shown a vast amount of patience and care through these constructions, and I'm absolutely thrilled to see that you at no point tried to turn these exercises into performances. You stuck to the construction the whole way through, applying the concepts covered in the lesson, subdividing everything to a considerable degree of precision, and allowing the resulting object to emerge from the forest of lines rather than dragging it out with overzealous line weight.
I can also see that you've definitely been learning from each of these - you definitely have your fair share of successes early on, but comparing the charger towards the beginning to the mustang at the end, the confidence you have working in 3D space with these kinds of constructions increases considerably.
When it comes to advice, what I can think of is fairly minimal. One thought that comes to mind is simply that this motorbike must have been inordinately challenging, given how little room you gave yourself to actually work through it. It's always clearer in hindsight once the drawing's complete, but there definitely was a lot more space you could have given yourself on the page to make some of the more superficial navigation of the forest of construction lines easier, and to ultimately get more out of the exercise. Really though, that's just me nitpicking.
As a whole, you've done an amazing job and should be very proud of yourself. I'll go ahead and mark this lesson, and the course with it, as complete. Congratulations!