See this page for more information about what this program is all about.
Click "Draw New" to begin with a random rule. "Refresh Current Rule" will keep the same rule from the previous drawing (but any change in the number of colors is ignored), but adjust the other options if they have been changed. "Reset" returns the form elements to their defaults, but doesn't redraw the image. "Pause Scrolling" will toggle animation of the image (slower for lower magnification levels).
Here is a larger version of this program more suited to desktop browsers.