How wide can a wide screen for motion-picture projection get? According to Walt Disney, the screen eventually will encircle the audience and, to demonstrate this, his engineers have designed and installed "Circarama" at Disneyland in Anaheim, Calif. The Tomorrowland section attempts to show what life will be like in 1986, with Circarama, sponsored by American Motors, as the theater of the future. Eleven cameras film Circarama, and 11 projectors screen the films.