Hey there, Mara. Congratulations on completing your 250 box challenge! I am glad to see the progress you have made throughout the challenge and while there are things you can continue to work on, you have accomplished what is expected for this challenge.

First, regarding your lines - you have made some good improvement in line confidence by the end, and while there are still times where you may have rushed or "misfired" your line, overall they are looking good. At this point, you should start to consider more line weight around the silhouette as explained here.

Now moving on to your boxes themselves, you are definitely being mindful of your convergences. You are still having issues with your back lines converging with your other lines, but that is common at this stage, and uncomfortable has made this infographic to further explain how to approach drawing parallel lines in perspective. So the main point of this is you should be looking at all parallel lines (in a box there are three sets of four lines) as a family. They are all related to one another by the vanishing point and the location of the vanishing point dictates that angles between them. Often times when we first start to draw boxes we focus on one plane at a time with its two paris of parallel lines and we make sure those lines are nice and converging appropriately. Then we move on to the next plane while not taking into account the first plane we drew. This often ends up with having two distinct points of convergence instead of the one correct point. With this in mind, keep practicing boxes in your warm ups and try to focus on drawing one line with the other three parallel lines in mind. Overall though you have followed all directions, applied your extension lines, and grew throughout the challenge. I will be marking this challenge as complete, congratulations!