Patented by K. Minami and T. Nishimiya 1984, made by Tomy.
(plastic with colored metal ball bearings, 4.3 inches square by 1/2 inch thick)
Turning a wheel on the side causes the center ring to turn one direction and all the other rings to
turn in the opposite direction. When solved, the center ring and three of the outer rings have
silver ball bearings, and the other three outer rings have bearings colored red, green, and blue,
and the center ring is missing one ball bearing. The one missing bearing allows bearings to be moved
around by turning the rings and transferring a bearing from one ring to an adjacent one that
currently has the empty position. After mixing it up, it is difficult to get it back to the solved
position because rings cannot be rotated individually.
Minami and Nishimiya Patent,
from: www.uspto.gov - patent no. 4,468,033