A method and apparatus that permit anti-knock control without the use of separate knock detectors as well as controlling the basic ignition timing from the output of a single engine speed sensor. The receiving container includes a bottom plate, first through fourth sidewalls and a first LGP fixing portion. Different embodiments of the connectors allow them to adapt to most wood-frame and masonry homes, and to most roof pitches. The difference in display period between subfields becomes smaller per one subfield or per several number of the subfields as the display periods become longer. Other aspects of the invention pertain to methods of forming such stents and methods of using such stents.