250 Box Challenge
Additional Box Exercises
Listed here are a couple variations on the basic box exercise that should be left until after you're fully comfortable with constructing individual arbitrarily rotated boxes in 3D space. These modifications can help develop one's understanding of 3D space further, but if the basics are not grasped solidly enough, they will merely serve as a distraction.
Boxes on a string
I'd recommend tackling lesson 2, or at least reading the section in that lesson about thinking in 3D, before tackling this exercise.
This one's a combination of the rotated boxes and organic perspective boxes from lesson 1. Start by drawing a line that swoops through 3D space, then place boxes along it, as though they're all connected by a string and being pulled along.
This one's complicated enough to merit a video. It discusses how we can take a box and start cutting it up into many smaller boxes. We also discuss the accumulation of errors that occurs when we approximate, and how to stay on top of them as you push through a construction, rather than trying to avoid them outright.