This is a fun little applet that lets you draw rotationally symmetric pictures. Draw with your mouse (or finger if you're on a tablet!). The controls should be pretty self-explanatory. The best way to learn how to use it is through experience, so try it yourself!
Java Runtime Environment (JRE) version 5 or higher is required to run this applet. If the applet above did not start, try installing the latest version of JRE from Oracle.
Get the source code here