A process for producing a light-reflective film is disclosed. According to various aspects, an incident electromagnetic wave is transmitted within a conductive enclosure. This is difficult under the state of the art. By performing this clustering, blocks with a high number of IO operations are grouped and stored on fewer tracks than if they were scattered across numerous tracks. In another implementation, the touch-screen user interface identifies and filters electronic books based on book size andor a time available to read a book. The prisms have the vertical angle of 50\xb0 to 75\xb0 and are arranged with a pitch of 10 \u03bcm to 150 \u03bcm.