I admit...this almost makes me wanna be a Slytherin...
This one is very different from the first two. I felt Slytherins in general would be more fond of order, hence the symmetry. And the simple color scheme isn't as bad as it seems, since you get color from the lake out the window. the lake is as much a part of the room's decor as the room itself
~Whisper
Edit: I feel the need to point out that these are out of my head, not based on the descriptions provided on Pottermore. Just in case people are wondering why I'm right on some counts and not on others
WOW this is just WOW! This is amzing! Do you think i could build a model based off of these designs if i credit you and give a link to the original designs. I've been wanting to build a model of the houses for a while but im not good at creating architecture and when i found these designs i could just picture it in my mind and it seemed like it would look so cool and be so much fun to make. I understand if you say no though.
I feel really bad about telling you this but i think i bit off a bit more then i can chew and i wont be able to do it or at least not any time soon. Soooooo im just gonna crawl under a rock in shame and say im sorry.