In a Vast, animated diorama covering the end wall of the Electricity and Communications building, three phases of California's development are portrayed. On the left is a covered-wagon train of 49 encamped for the night in a Sierra pass. On the right is a dock scene in early-day San Francisco - a sailing ship rocking with the tide, a stage coach awaiting its passengers. In the center panel is the artist's conception of the City of the Future. Fifty animated figures give the diorama life and reality. Changing light effects playing upon the richly colored backgrounds of mountain and bay scenery add beauty and charm to the picture. Beneath, at floor level, is a series of other exhibits presenting the advantages of electric utility service and the extent of the company's system. At the Pacific Gas and Electric Company Exhibit. Electricity and communications Building - on Treasure Island in San Francisco Bay.