I just finished the challenge, so consider this a critique from a person on the same level as you. While your boxes are neat, the lines don't converge except for a few. Add line weight on only one corner. In a lot of boxes, the structure is wrong and the lines are lopsided in a lot of the places they shouldn't be. For example, box 234. Your line work is very neat but I'm afraid you haven't grasped the concept. I'd like you to go through the written content+ the video. The video explains very well how the lines converge. That's about it, I'd like to see some revisions.

That'll be all,

lemons_and_roses