Your project seems really cool ;-) I really like the simplistic graphics! The integrators are my favorite part of the simulations :-D It's really interesting to compare the different integrators around. In this simulation that is written in Javascript I have implemented most of the integrators (all except Euler and RK4):
[https://thehappykoala.github.io/Harmony-of-the-Spheres/#/scenario/The%20Sun%20and%20the%20Neptunian%20System](https://thehappykoala.github.io/Harmony-of-the-Spheres/#/scenario/The%20Sun%20and%20the%20Neptunian%20System) If you click the Physics tab on the right you can choose from a whole range of them and compare them. It's first then you realize how horrible Euler's method is XD. It would be fun helping you in implementing some of those ;-)
