The iconic representation shows schematics of the North, East, and South elevations of the house.
The diagram representation is interesting too. Here, we overlaid four different models, the models of the four rooms onto the same space on the screen. The four models have transparent backgrounds, thus they are visible to the top layer, except in places, where different models have lines at the same locations. The living room model is the top layer. Therefore, the walls of the living room are grey, whereas those of the other rooms are green (they actually come from the living room model).
The actual "model" here consists of the four connections in the colors red, lilac, yellow, and blue, as well as the connections from the six tabular functions.
Enjoy!