An assignment server receives two or more data blocks of the file from a client. An elongated band forming an approximately circular shape with opposite ends of the band contacting each other defines a base edge received within the circular peripheral groove in an abutting relationship with an inner edge of the groove. Arriving packets are differentiated according to the particular distribution compartment to which they belong. When the difference value exceeds a predetermined concentration threshold, a high-concentration signal is generated to close a flap. Thickness variations outwardly from the stability plane are disclosed, along with density variations to achieve a similar greater than natural stability. This control signal can be used, for example, the reduce the volume of audio reproduction.