Conservative motion of a discrete, tetrahedral top on a smooth horizontal plane

Tetrahedral tops are simulated as discrete, rigid bodies in rotation by int roducing a molecular mechanics formulation. The contact point of the top wi th the (X, Y)-plane is allowed to move in the plane. The conservative, dyna mical differential equations are solved numerically in such a fashion that all the system invariants are preserved. Examples, which include cusp forma tion, and looping, are described and discussed.