For the first 50, while your convergences are generally accurate, there are some instances where a line will veer off in the wrong direction, like with box 14, box 31, and box 50. I also noticed some lines arcing a bit, like in box 8 and box 19, but your lines improve towards the end of the set.

For the next 50, there are a few more instances of errant lines, like in box 61, box 80, and box 97. I also saw a few cases where lines appeared to pair off and converge towards two vanishing points, like in box 84. Despite the odd errant lines, your convergences show continued improvement in this set.

I did see a few minor instances of arcing and wobbling, like box 67 and box 82, though your lines smooth out shortly after they appear.

For the last 150, there is continued improvement in the accuracy of your convergences. I did see a few more instances of lines pairing off, like in box 123, box 158, and box 214. In these boxes, the inner lines (green and orange in this diagram) diverge instead of converging at the vanishing point. Keeping in mind the angles of neighboring lines can help when planning the box's construction.

I also noticed a few more wobbly lines in this last set, like in box 119, box 167, and box 207. However, as before, it smooths out quickly, and your lines show further improvement at the end.

As an aside, a few of your line extensions, like in box 204, appear to have been drawn in black or dark brown. I recommend against using a color that dark, as it makes it harder to see the original lines that you drew for the box. Also, box 233 and box 239 are missing some line extensions.

All said, I'm going to mark this challenge as complete.