Geomag
The basis of the Geomag magnetic toy (geometry - magnetism) was patented in 1998 by Claudio Vicentelli. The system consists of plastic struts with a small recessed magnet embedded at each end, with a raised circular plastic rim that mates with a ball bearing, held in place by the magnet. Up to six struts can be attached to one metal ball when arranged in a plane, and more struts if the arrangement is three-dimensional. The friction of the circular plastic rim against the ball is enough to produce movable but semi-rigid joints.
The ability to quickly snap together joints at free-form angles, and then adjust them to produce alignments with other joints allows complex three-dimensional structures to be built up quickly, as long at the length of all the joints is the same.
This makes Geomag especially useful for making and playing with abstract geometrical structures.
