I did the lower left one once in school and got in trouble for it over not using color. Actually even moreso, since I did not use any shading and deliberately did it in a binary Tracer Bullet sort of style.

Of course, no part of the assignment specified that you had to use any particular colors, or even use colors at all. But apparently the moronic student teacher overseeing the art class that semester retroactively decided that this was “wrong” and that she was going to turn it into a big deal and make herself look monumentally stupid in front of everybody in the process. In response to her threatening to give me a zero for the entire assignment if I did not give in and use color, I responded by meticulously replacing the entire background with the brightest neon orange paint I had on hand (which as I recall was actually an airbrush paint) and still left the rest in stark black and white. There, color applied.

When this incited the nutty bitch to try to escalate again I took it to the administration who wanted nothing to do with it and passed it back to the actual art teacher. I won, she lost; When our creations were eventually put on rotation in the school lobby mine was visible from the street through the door. It was probably visible from space.