Abstract: One embodiment of a device for producing a net unbalanced propulsive force has several wheels 24 rolling on a circular track 26 and angled to the plane of the track, such that every element of the wheels describes a repeating angled arcuate path. Precession of each “half-wheel” thus operating produces an unbalanced force normal to the plane of the wheel, with two components: 1) one that cancels all around with those of the other wheels, and 2)one that adds to produce a propelling force normal to the plane of the track. Other embodiments are described and shown.

Abstract: A toy having an elongated handle connected by a flexible driving line to a whirling assembly comprising two flat rings joined together by a flexible connecting line. The driving line is connected to the whirling assembly by a double swivel connector, which is located beside one of the rings and permits rotation of both lines within the swivel. The rings rotate about an axis midway between them as the free end of the handle is rotated, and several different recreational exercises can be accomplished by different manipulations of the handle. In alternative embodiments, different swivel arrangements are provided to prevent twisting of the driving line and winding of the driving line around the connecting line.