The PCs will ordinarily enter from through the "Near Wall". The entire wall slides away on rusty rails at a touch.
What they see when the wall pulls away is a room with walls made of different colored material and a pit with spikes in it where the floor should be . (Pit has slippery walls and it's an intimidating drop. The spikes are too close set to allow climbing down there and passing through normally.)
The black wall has a square opening big enough for a human to fit through in the center. Touching the black wall causes the room to rotate counterclockwise 90 degrees--the black and white walls maintain their position relative to each other but the spiky pit becomes the right-hand wall, the white wall becomes the floor, etc. Touching it again will rotate it 90 degrees again, making the grey wall the floor, etc. etc..
Touching the white wall/floor causes it to move quickly toward the metal wall and mash anything on in the room against it.
Touching the grey wall/floor causes it to move quickly toward the spikes and shove anything in the room onto them.
The metal wall/floor is inert.
This is the simplest cubey trick room. (Connie and KK successfully navigated it last night, but only after using a loyal wardog as a guinea pig.) They get more complicated later.