Okay, Im glad you found it useful and that you are willing to afron the mistake, thats really important for moving forward. That said, I think that in your last two boxes there is a huge improvement on convergence, there is still some calibration issues, but I think that you are starting to understand what you need to be aiming for with your boxes.

This said, whenever you are drawing your lines so they go towards a vanishing point, you need to take into account how that line will relate with the other lines in the set so you can guess more accuractely. I know how confusing it sounds, but here is a diagram that explains it better, just look at it from time to time and it will eventually click. Im confident on explaining you this because you showed that you understood what I told you on the last revision!

Also check this method of construction to solve the back cornern issue.

Now, we are going to make some more boxes so you can get some practice with this new concepts, Im not aiming for you to hist these perfectly, as I said I want you to have some room for playing with this elements before you move on with the course.