You can adjust the time delay between two springs(emulate strong or weak interaction between springs), this will affect the wave-speed.
Change the spring constant will change the frequency of virbration. (or frequency of wave)
There will be two sets of particles when k1 and k2 are not the same (emulate wave propage from one medium into another medium).
Because the wave-speed is the same, so those two waves have different wavelength.
The wavelength will be calculated and displayed when the simulation is paused.