Hi, I'm PGcools and I'll review your work.

It's gonna be quick, as there's not much to point out, you made a really good job.

Lines

Your lines are very good. There are just wobbly in a few intances and sometimes arching, especially in Ghosted Planes. Make sure you are drawing with your shoulder and try to arch the lines to the opposite direction while ghosting to avoid it.

Ellipses

Again, there are pretty much correct. I notice some wobble here too, but it's not abundant. And you tend to overshoot the ellipses rather than falling short it their placement, so keep that in mind.

Boxes

Fine too. Just make sure to not repeat the lines even if there are very off. Keep on working with the off line. In Rotated Boxes there are two boxes missing at the bottom, and remember to use the lines of the later boxes to help you draw the boxes ahead. There's not much else to point out, some lines in Organic Perspective are diverging, but you will work on that on the 250 boxes challenge.