This demonstration illustrates a simple phase plane plot. The particular system plotted in this example is
To plot the trajectory that starts at any specific point, just click the mouse there. The programme stops plotting a trajectory when it reaches the edge of the screen or when the user clicks the "Stop" button. The user may clear the screen by clicking the "Clear" button. By default, trajectories are plotted forwards in time. The user may also chose to have trajectories plotted backwards in time. Just click the "Forwards" button. It toggles between "Forwards" and "Backwards".
The demonstration below is an applet. Google Chrome, Firefox, Safari and Microsoft Edge no longer execute applets natively because of security issues with NPAPI plugins. However applets can be played in the Google Chrome browser by using the CheerpJ Applet Runner extension.