Wow, looking at these I struggle to come up with any criticism except that your line quality descends into very scribbly lines during the texture exercises. Also the arrows to not consistently get thinner towards the „back“ and instead vary in width.

The hatching on the intersecting boxes is a bit much and somewhat distracts from the actual focus of the exercise but that is nitpicking.

I am not sure about how „correct“ the intersections are but the pictures look good to me.

Overall the only thing I’d really suggest is to keep using the same confident lines in your textures that you use for the other exercises. As uncomfortable pointed out in one of the videos: „once you are about to scribble, stop.“

Allthough i would not call your lines random, you could achieve a better effect with clearer lines.