Abstract: Disclosed in the present invention is a novel bottle cap having interlocking function in addition to its function as a conventional bottle cap, whereby a plurality of the caps can be interlocked together to make desired geometrical constructs for entertainment, education, or collection purpose. Also disclosed are methods of reusing bottle caps so that littering of bottle caps to the environment can be reduced.

Abstract: An electronic dart game includes a dart and a dartboard provided with a frame and a main body for being shot by the dart. The dart game can be scored automatically for being provided a plurality of inductance coils on the frame and connected to a electronic scoring means. A point or a slender shaft of the dart is magnetized so that an electronic signal can be generated while the dart is shot to go through the inductance coils in accordance with the Lenz's law. Therefore, the chances for erroneous signal to occur are very slim. As the main body is designed directly to the frame, the dartboard has a stable one-piece surface, thus a player will have a similar satisfactory sensation as shooting onto a classical one-piece dartboard.

Abstract: A magnetic dart board that includes embedded conductor coils beneath scoring areas. When a dart with a magnetic head strikes a scoring area of the dart board a current is induced in the underlying conductor coil. The induced current provides an electrical signal that is transmitted to an automatic scoring system that calculates and displays scores. The dart board is made from a plurality of layers including a top layer, an insulating layer, a sensing layer and a body layer. The multi-layered dart board is flexible and can be rolled up for storage, shipping and transportation.

Abstract: A dart having a substantially hollow shaft and one or a plurality of removable weights to be placed in the lumen of the shaft so that the weight of the dart is adjustable and there is a secondary momentum when the dart hits a dartboard, wherein the weight is magnetic or non-magnetic.

Abstract: A magnetic dart board that includes embedded conductor coils beneath scoring areas. When a dart with a magnetic head strikes a scoring area of the dart board a current is induced in the underlying conductor coil. The induced current provides an electrical signal that is transmitted to an automatic scoring system that calculates and displays scores. The dart board is made from a plurality of layers including a top layer, an insulating layer, a sensing layer and a body layer. The multi-layered dart board is flexible and can be rolled up for storage, shipping and transportation.

Abstract: An electronic dart game includes a dart and a dartboard provided with a frame and a main body for being shot by the dart. The dart game can be scored automatically for being provided a plurality of inductance coils on the frame and connected to a electronic scoring means. A point or a slender shaft of the dart is magnetized so that an electronic signal can be generated while the dart is shot to go through the inductance coils in accordance with the Lenz's law. Therefore, the chances for erroneous signal to occur are very slim. As the main body is designed directly to the frame, the dartboard has a stable one-piece surface, thus a player will have a similar satisfactory sensation as shooting onto a classical one-piece dartboard.