Three-Body Problem in 3D
In the classic three-body problem, point masses with initial positions and velocities can result in very complicated trajectories.
The equation of motion is
where is the acceleration of the body, is the mass, and is the vector connecting the masses and .
 J. C. Sprott, Elegant Chaos: Algebraically Simple Chaotic Flows, Singapore: World Scientific, 2010 pp. 121–123. www.worldscientific.com/worldscibooks/10.1142/7183# t=aboutBook.