The Ejs Anisotropic Oscillator model displays the dynamics of a mass connected to two opposing springs.  The simulation displays the motion of the mass as well as the trajectory plot.  The initial position of the mass can be changed by dragging.  The unstretched lengths of the springs can changed as well via textboxes.  You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item.  

Ejs Anisotropic Oscillator model was created using the Easy Java Simulations (Ejs) modeling tool.  It is distributed as a ready-to-run (compiled) Java archive.  Double clicking the ejs_ehu_oscillations_anisotropic.jar file will run the program if Java is installed.  Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models.  Additional Ejs models for classical mechanics are available.  They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Please note that this resource requires at least version 1.5 of Java (JRE).