The code used in in the following Youtube video: https://youtu.be/mQqMUZqpkZw
This uses two simple methods to solve the follwoing ODE: dy^2/dt^2= -(k/m)*y -g
This corresponds to a mass oscillating on a spring without damping. The Explicit Euler method is demonstrated to be unstable, while modified Euler method remains stable for all time.