1:20 AM, Friday September 25th 2020
For this challenge you should only rely on your eye. Basically, if you can't fit the ellipse into the box correctly (touching the contact points and following the minor axis), it will mean that the box ends aren't squares. Use that knowledge to modify them over and over, and by trial and error you will naturally start to get better at it.
On lesson 7 you will learn how to construct a cube with ellipse guides, but for this challenge like I said the objective is to train your eye, so keep pushing through and doing your best to do it. Good luck!