Novel electrically conductive polymer composite structures having a horizontal plane that contain effective amounts of two different types of conductive graphitic nanofibers. The contents of all storage locations are organized into a predetermined format using a signal indicating whether the input code is of the first or second type. The present block metal body after reduction has prismatic particles complicatedly entangled like a root so that the pore of the metal powder is open. The surface of the light-emitting diode with the covering layers is smooth.