A sheet of plastics material is continuously extruded onto the upper run of an endless conveyor which carries aluminum vacuum mold plates each defining a cavity with a shingle pattern. In an arrangement, rotational motion of the motor enables the aerodynamic control surfaces of a rotating projectile to oscillate and thus vary the angle of the control surfaces as the projectile spins. The base station processes the data so that the data can be display by an ECG monitor. It is possible to provide a sports implement that is favorable in operationality and friendly to many users in a wide range regardless of the muscle strength or physical constitution and the like of a user, since the user can adjust characteristics of a sports implement. To read a word from the memory array, any data stored in the redundant columns is first read out, and then the data from the primary columns is read out, bypassing the previously identified defective column groupings. In some embodiments, the naphthalene core of these compounds are mono-, di-, or tetra-substituted with cyano group or other electron-withdrawing substituents or moieties.