Set it to Turbo Mode (shift-click the green flag) to make it faster, if you wish.
Basically a test for planetary simulations. Check out the code on Sprite1, it contains the calculations for acceleration. -m1 and m2 are the masses of the planets, in kilograms. -r1 and r2 are the radiuses of the planets (not used). -a1 and a2 are the planets' accelerations, in meters per seconds squared. -r is the distance between the planets in meters. I don't yet know why they jump away whenever they hit each other. Maybe someone else can figure that out.