The GR Kerr Stone program simulates orbits of an object in the equatorial plane near a rotating black hole using the Kerr metric. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the gr_kerr_stone.jar file will run the program if Java is installed. The default is an object initially with an r value of 3.0 near a black hole with angular momentum parameter, J/M = 0.75.
Quelle: Open Source Physics