Yellow Rooms
There seem to be exactly 21 Yellow Rooms:
10 one-way rooms
9 two-way rooms
1 three-way room
1 dead end room
If you look closely, you can see that there' are three different room formats:
Double: Access a door to reach an upper platform. Werewolves cannot cross the platform.
Small: The smaller ones.
Large: The...larger ones? xD
Look at how they're grouped. They're the EXACT same rooms, right down to the floor tiles and the hardened drippings on the wall.
The only thing that differentiates them are the various cave accessories (pillars, stalactites, boulders, torches, etc.) that adorn the room and even cover the doors. Look at the dead end room: you can see all those doors blocked right?
Night Frights and Big Dogs seem to prefer to appear in the Double and Small rooms, though they've been sighted in the Large rooms.