The reciprocating saw has two, superimposed, blades having a common axis and arcuate cutting surfaces adjacent each other. Upon receiving content, the client divides the content into smaller data-blocks of a predetermined size. The logic state transition sensor circuit may include a sensing circuit containing sensing and amplification elements and a recording circuit containing recording elements. Moreover, the translucent portion rib extends a from the third wall, and a first distance between the translucent portion rib and the first wall is less than a second distance between the signal blocking member and the first wall.