Editor: This program allows the user to places masses on a two-dimensional space, and give them various mass and initial velocity. Then you can observe as objects interact with each other gravitationally. Some might orbit each other or they might just swallow each other up! See if you can simulate a Sun-earth-Moon system, or a binary Star system or a Black Hole! This should be fun for physics or astronomy classes as they explore the inverse-square law of gravity.