This Demonstration shows the dynamics of a 3D spring-mass system consisting of nine identical masses arranged in a body-centered cube and connected by 20 springs. The effect of gravity is assumed to be negligible (as in outer space, for example). The springs are assumed to have the same force constant and damping coefficient. The mass at the center is fixed at the origin, while the eight outer masses can be moved.
The system without damping exhibits chaotic dynamics; with damping the system gradually relaxes back to its equilibrium configuration of a body-centered cube.
To get a general idea of the dynamical behavior of this system, it is sufficient to move just three or four of the masses.