Hollow ball of mass of 4Kg and diameter of 10cm. It collaborates with the base as follows: We can fill the ball with glycerol or other viscous liquid and suspend it from thread of suitable length. During the oscillation the glycerin is poured from a special small orifice on the base. The shape created is associated with the Foucault pendulum and the Lissajous patterns. The heigh of the base is adjustable.
Max Kohl, Chemnitz No 52129