| 摘要 |
The top side (11) of the plate (1) has a cavity (20) near its periphery for the thumb of the throwing hand, whilst the bottom side of the plate has parallel grooves (30, 40) for the fingers of the throwing hand. The convex side of the groove faces away from the thumb cavity. The grooves and thumb cavity are arranged essentially mirror symmetrical in relation to a symmetry plane that extends at right angles through the top and bottom sides of the plate. |
