A microcomputer detects tracing on a touch panel, detects the traced pattern and controls each unit to execute advancingbacking or deleting the image according to the detected pattern. On the bottom surface of the layered substrate, there are provided a plurality of functional terminals for inputting and outputting signals relating to functions of a circuit inside the layered substrate, a plurality of ground terminals, a plurality of terminals that are not connected to external circuits, and a conductor section for grounding. Each of the movable rails is pivotally supported so as to be horizontally rotatable about a vertical spindle at each outer end portion positioned outside of the crossing aisle. The password table and the indication table are stored. A ball valve in the passageway to the sensor static port achieves a small delay. The speaker is supported relative to the ceiling so as to extend through an aperture in the ceiling.