To the right is a simple example of an embedded applet, in this case a Java applet that demonstrates binary search tree (BST) rotations. This is a complicated concept in computer science, associated with data storage and searching algorithms. The interactive applet (the user can click on the balls to "select and rotate" the data) helps illustrate the principles in an easy to use and effective manner.
Note how the HTML content of the APPLET element is not displayed: the content is alternative markup, that is displayed by browsers that do not understand the APPLET element or that are unable to run Java applets.
This applet example is courtesy of James Stewart, an Assistant professor in the Department of Computer Science, University of Toronto.