A Moiré pattern is an interference pattern produced by overlaying similar but slightly offset templates. A simple example is obtained by taking two identical ruled transparent sheets of plastic, superposing them, and rotating one about its center as the other is held fixed.

Moiré patterns can also be created by plotting series of curves on a computer screen. Here, the interference is provided by the discretization of the finite-sized pixels. For example, the illustrations above show a number of concentric circles plotted with a range of uniform spacings. Note the phantom lines and curves that appear.

REFERENCES:

Amidror, I. The Theory of the Moiré Phenomenon. Dordrecht, Netherlands: Kluwer, 1999.

Cassin, C. Visual Illusions in Motion with Moiré Screens: 60 Designs and 3 Plastic Screens. New York: Dover, 1997.

Firby, P. A. "Controlling Interference in Graphics." Math. Gaz. 71, 119-125, 1987.

Grafton, C. B. Optical Designs in Motion with Møiré Overlays. New York: Dover, 1976.

Oster, G. and Nishijima, Y. "Moiré Patterns." Sci. Amer. 208, 54-63, May 1963.

Strong, C. L. "The Amateur Scientist: Moire Patterns Draw Contours, and a Meter Determines Current in Electrostatic Circuits." Sci. Amer. 229, 120-125, Nov. 1964.