To provide an optical pointing device capable of being provided as a device of short stature, being used integrally with an apparatus having a limited stature and a limited space, reducing cost and improving reliability. Each sub-image is displayable by a display device. A method of introducing a gaseous anaerobic fertilizer into the landfill is also provided. A multithreaded process is used to send the first document information to the first recipient system set and the second document information to the second recipient system set. The processor may comprise a computer and computer program that converts the data to frequency information, analyzes the frequency information to identify a peak frequency, compares the peak frequency to the characteristic frequency vs.