If for whatever reason you have time and would like to make a contribution, I think doing so should be quite easy as I think you'd just have to subclass the Eul

If for whatever reason you have time and would like to make a contribution, I think doing so should be quite easy as I think you'd just have to subclass the Euler class. You can get an idea of how to do this by looking at how I did it with the RK4 subclass (https://github.com/TheHappyKoala/Harmony-of-the-Spheres/tree/master/src/js/Physics/Integrators https://github.com/TheHappyKoala/Harmony-of-the-Spheres/tree...). If not, I'll add Verlet integration myself one of these days, but right now I'm working on introducing a particle system so that I can simulate the rings of Saturn (the particles will feel the gravity of all the masses in the simulation, but they won't exert a gravitational force on the other particles and masses in the simulation; this way you should be able to have fun distorting the rings of Saturn with a celestial object of your choice).