This excellent demo comes from David Anson, a student
at Cornell. His other demos for the project in which he produced this are
at his web site.
Mach Banding Interactive Demonstration -
A phenomenon whereby piecewise linear intensity changes across a polygon
boundary trigger the human visual system into perceiving the boundary as
a bright band (3D Computer Graphics by Alan Watt, page 132).
The Java applet below lets you experiment with this phenomenon. Play
around with the settings to see what effect they have on your perception
of the Mach Banding. Different combinations of colors, bar widths, and
the presence of separators have a big impact on the eye's perception of
NOTE: The applet is reasonably intelligent about updating the display (try
hitting "Enter" after making a change), but you can force a repaint
at any time by pressing the "Repaint" button.