There are some fundamental problems with your boxes. The sides tend to not align to the same vanishing point, and at times break the ">90 degree rule", i.e. the angles between the edges of the 3 planes facing the viewer should all be greater than 90 degrees. This was explained in lesson 1, I believe. I suspect you didn't do the 250 box challenge, or lesson 1. The markmaking is sort of off, but that shouldn't have been a problem since you're encouraged to use a ruler for this lesson. The form intersections do however show better markmaking and understanding of 3D space, but the ">90 degree rule" is something to be aware of.