You pick a color and draw with your mouse. Whatever you draw in one sector is mirrored in all others.
The figure above was drawn without a lot of throught in about 15 seconds.
So, it's easy and fun--mostly for the kids.
In the image above there are 20 plane of symmetry. You may save and print out your creation.
You may download a version for the Mac (OS X) here, and the Window's version here.
I am less confident about the Windows version than the Mac.