An intraluminal stent and graft includes a stent made of a continuous helix of zig-zag wire and loops which connect adjacent apices of the wire. A recording medium built in a recording medium unit has a storage region for storing keywords used in this setting. Monocentric lenses in accordance with the present invention include a spherical central lens element and a plurality of lens shell sections that collectively reduce at least one of spherical and chromatic aberration from the magnitude introduced by the spherical lens element itself. A piconet operable device operating therein includes intelligence such that it may detect a symbol that has undergone an undesirable symbol collision.