You can now create a RoomVisual object using the constructor without a roomName parameter and post visuals to all rooms simultaneously:

new RoomVisual() .circle (30,30, {fill : 'red' }); new RoomVisual( 'W1N1' ) .rect (10,10,40,40);

This code will display both the circle and the rectangle in the room W1N1, and only the circle in any another room.