Enneagram
From Wikipedia, the free encyclopedia
In geometry, an enneagram is a nine-pointed geometric figure. The term derives from two ancient Greek words: ennea (nine) and gramma (something written).
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[edit] Regular enneagrams
A regular enneagram (a nine-sided star polygon), is constructed using the same points as the regular enneagon but connected in fixed steps. It has two forms, represented by a Schläfli 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.[1][2] (If the triangles are alternately interlaced, this results in a Brunnian link.) This last is sometimes also called a nonagram. This geometrical figure should not be confused with the logic puzzles called nonograms.
 Complete graph K9 |
 Enneagon {9/1} |
 Star polygon {9/2} |
 Star figure 3{3} |
 Star polygon {9/4} |
[edit] Other enneagram figures
 The final stellation of the icosahedron has two isogonal enneagram faces. It is a {9/4} wound star polyhedron, but the vertices are not equally spaced. |
 The Enneagram of Personality and the Fourth Way teachings use an irregular enneagram consisting of a triangle and an irregular hexagram. |
 The Bahá'í nine-pointed star |
[edit] Use in popular culture
- The heavy metal band, Slipknot, uses the |9/3| star figure nonagram as a symbol.
- The nine-pointed star or nonagram can symbolize the nine gifts or fruits of the Holy Spirit.[3]
[edit] See also
[edit] References
- ^ 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.
- ^ Our Christian Symbols by Friedrich Rest (1954), ISBN 0-8298-0099-9, page 13.
