@Override
 public void actionPerformed(ActionEvent e) {
   String command = e.getActionCommand();
   switch (command) {
     case "New":
       stop = false;
       step = 0;
       model.resetAttractor();
       model.startwerte(); // set initial values
       model.treibwerte(step);
       model.repaint();
       break;
     case "Start":
       stop = !stop;
       start();
       break;
     case "Friction ++":
       model.frictionPlus();
       break;
     case "Friction --":
       model.frictionMinus();
       break;
     case "Phi1 +":
       model.phi1Plus();
       break;
     case "Phi1 -":
       model.phi1Minus();
       break;
     case "Phi2 +":
       model.phi2Plus();
       break;
     case "Phi2 -":
       model.phi2Minus();
       break;
     case "Phi3 +":
       model.phi3Plus();
       break;
     case "Phi3 -":
       model.phi3Minus();
       break;
     case "Phi4 +":
       model.phi4Plus();
       break;
     case "Phi4 -":
       model.phi4Minus();
       break;
     case "Trajectory":
       gui.buildTrajectorySettings(numberOfTrajectories, model.getLimit(), this);
       break;
     case "Trajectory 1":
       colorChooser(1);
       model.setTrajectoryColors(getColors());
       break;
     case "Trajectory 2":
       colorChooser(2);
       model.setTrajectoryColors(getColors());
       break;
     case "Trajectory 3":
       colorChooser(3);
       model.setTrajectoryColors(getColors());
       break;
     case "Trajectory 4":
       colorChooser(4);
       model.setTrajectoryColors(getColors());
     case "Limit":
       model.setTrajectory(numberOfTrajectories, gui.getLimit());
       break;
   }
 }
 public QuadBarPendulum() {
   gui = new QuadBarPendulumView(this);
   model = new QuadBarPendulumModel();
   model.setTrajectoryColors(getColors());
   gui.addPanel(model);
 }