2:41 PM, Friday May 22nd 2020
Thank you for your answer. It's right that at the beginning I made some mistakes about the extensions of the lines (not in the right direction) but I think I figured that out afterwards.
One thing that was difficult to me (and still is) was which side to shade when you see for instance 2 sides of the box and the side that is up. I wasn't able to say which face was closer to the viewer. It might look stupid but it really was a problem for me.
I don't understand, what do you mean by "different kins of Y intersections"? I did realize that my boxes all looked almost the same but with the Y method, I thought I didn't have many possibilities.
Thanks again for your critique.