Disclosed are systems, apparatus, methods, and computer readable media for creating and sharing social files in a feed system. Said installation is enhanced by adding thereto an auxiliary electric power distribution line, and a filtering circuit interposed between the electric power distribution line and the auxiliary electric power distribution line. A base holds rotatably each rotatable particle. The cover and the bezel cover the display panel together. A transmission is directly coupled to the output shaft of the motor. From the spatial, cross-correlated reference signal, structural information can also be obtained using techniques that allow size information of scatterers to be obtained from angle-resolved data.