- Enneagram
In
geometry , an enneagram is a nine-pointed geometric figure. The term derives from two Greek words: ennea (nine) and grammon (writ or draft).Regular enneagrams
A regular enneagram (a nine-sided
star polygon ), is constructed using the same points as the regularenneagon but connected in fixed steps. It has two forms, represented by aSchläfli symbol as {9/2} and {9/4}, connecting every second and every fourth points respectively.There is also a star figure, {9/3} or 3{3}, made from the regular enneagon points but connected as a compound of three equilateral triangles. [Grünbaum, B. and G. C. Shephard; "Tilings and Patterns", New York: W. H. Freeman & Co., (1987), ISBN 0-7167-1193-1.] [Grünbaum, B.; Polyhedra with Hollow Faces, "Proc of NATO-ASI Conference on Polytopes ... etc. (Toronto 1993)", ed T. Bisztriczky et al, Kluwer Academic (1994) pp. 43-70.] This last is sometimes also called a nonagram. This geometrical figure should not be confused with the logic puzzles called
nonograms .Use in popular culture
* The
heavy metal band, Slipknot, uses the |9/3| "star figure" [http://www.slipknot-metal.com/main.php?sk=nonagram nonagram as a symbol] .
* The nine-pointed star or nonagram symbolizes the NineFruits of the Spirit .ee also
* List of regular star polygons
*Enneagon References
External links
* [http://mathworld.wolfram.com/Nonagram.html Mathworlds page about this figure including an illustration]
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