The simplest isometry, called bilateral symmetry, or mirror-symmetry, is reflection across a line. A figure with bilateral symmetry looks the same on both sides of a line except that the two sides of the figure are mirror images of each other. Figure 1a shows an example of a figure with a vertical line of symmetry. Figure 1b shows an example of a figure with a horizontal line of symmetry. Figure 1c shows an example of a figure with both vertical and horizontal lines of symmetry.
A simple flow chart can be used to easily classify any strip pattern with this 4-character code. This flow chart is presented by Dorothy K. Washburn and Donald W. Crowe, and is more completely described in Symmetries of Culture: Theory and Practice of Plane Pattern Analysis, published by the University of Washington Press.
credit to:
Symmetry Patterns of the Wisconsin Woodland Indians
Kim Nishimoto and Bernadette Berken
St. Norbert College
Prof. Dr. Marzita Puteh
