Abstract: Three rings of different diameters are pivotally interconnected at their perimeters so that they can rotate with respect to each other. The innermost ring, larger in diameter than the height of a man, is pivotally attached only to the intermediate ring on one axis. The intermediate ring is pivotally attached to the outermost ring on another axis. The outermost ring is supported by a pivotal mounting at opposite ends of a semicircular supporting bracket.A foot plate for supporting a man as the operator at the center of the innermost ring is mounted in turn on the lower edge of the innermost ring. There is a waistband for stability midway between bottom and top edges of the innermost ring and a handlebar at the same top edge.While the operator is taking his position on the foot plate, a locking bar holds all three rings in place in vertical position concentric with each other.