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Scientific, nautical, surveying, photographic, cinematographic, optical, weighing, measuring, signalling, checking (supervision), life-saving and teaching apparatus and instruments; apparatus and instruments for conducting, switching, transforming, accumulating, regulating or controlling electricity; apparatus for recording, transmission or reproduction of sound or images; magnetic data carriers, recording discs; automatic vending machines and mechanisms for coin-operated apparatus; cash registers, calculating machines, data processing equipment and computers; fire-extinguishing apparatus.
the invisible wall is a stereoscopic viewing device designed for creating changeable virtual floor space for dioramas and applied to education and entertainment. because stereoscopy creates the illusion of depth, the physical screen appears to disappear to create continuous space from the viewer to the yon clipping plane. the screen may be reflective or transmissive, polarization preserving or polarization ambivalent, multiple projectors or a single projector may be used to project the image onto the wall, or the wall may be a self-emitting. although referred to as a wall, the surface may be vertical, horizontal or at an angle to create the illusion desired. a typical example of the use of an invisible wall is to extend the visual floor space of a museum. in this case, a solid wall may be transformed into an apparent extension of the room by the use of stereoscopy. since most projected imagery is driven by a computer video server, the contents of this virtual space can be changed at will