These applets are all "live" on this web site. Their purpose is to illustrate [often by animation] various concepts and principles described in the text. Although the most popular web browsers are no longer Java-capable and therefore cannot run these applets, each applet can be launched as a stand-alone "Web Start" application by clicking on the static image of the original applet.
All these applets are designed to run under sandbox conditions. That is, none of them performs any input/output operations other than to input its own data from files within the '.jar' file that contains it. It does not — and cannot — gather or write any data from your computer's keyboard, screen or file system. Nor can it gather or write any information to my server.
† Since early 2019, due to the unfortunate retrogression in Web functionality, Java programs will no longer run at all in any of the popular browsers. I have therefore provided a link for each of the applets marked with a † to enable you to download and run it as a stand-alone Java program. Mainstream warnings notwithstanding, these programs will neither blow up your computer nor wreak any other kind of fanciful mischief. They simply draw and/or write on your screen. In the good old days these applets simply ran embedded within the web page where their static images are now displayed. The embedded applets still run in pre-2017 versions of browsers with Java 1.6 installed and the Web Start versions still run in pre-2019 versions of browsers with Java 1.8 installed. To read the rancid history of this sad retrogression in Web functionality, please click here.