Video signals from a plurality of personal computers are written to a memory that stores video signals for a plurality of display screens through respective buffers. The nanowires are characterized in that they are obtained by a novel method using novel precursors. A circulating pump withdraws water from the tank and pushes the water along a treatment conduit, the conduit containing an ozonewater mixer and returns the water to the treatment tank. At least part of the first electrode layer is in at least some perforations of the current collector. With this method, games proceeding simultaneously and in parallel in upper and lower spaces are displayed in the respective fields as seen from a viewpoint in the space. The increased size of the end parts prevent swellings that may occur during the production process.