Enneagram 183229 215482691 2008-05-28T11:58:50Z 68.183.195.96 {{for|the use of an Enneagram with personality issues|Enneagram of Personality}} {{for|the use of an Enneagram in relation to the teachings of [[Gurdjieff|G. I. Gurdjieff]] and his followers|Fourth Way Enneagram}} In [[geometry]], an '''enneagram''' is a nine-pointed geometric figure. The term derives from two Greek words - '''ennea''' (nine) and '''grammos''' (something written or drawn). [[Image:Enneagon stellations.png|thumb|150px|right|Enneagrams shown as sequential stellations]] [[Image:Enneagram.svg|thumb|The [[Enneagram of Personality]] and [[Fourth Way Enneagram|Fourth Way Enneagram]] use an irregular enneagram, constructed from a triangle and an irregular [[hexagram]].]] == 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}, made from the regular enneagon points but connected as a compound of three equilateral triangles.<ref>[[Branko Grünbaum|Grünbaum, B.]] and G. C. Shephard; ''Tilings and Patterns'', New York: W. H. Freeman & Co., (1987), ISBN 0-7167-1193-1.</ref> <ref>[[Branko Grünbaum|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.</ref> , this last is sometimes also called a [[nonagram]]. {| class=wikitable |[[Image:Complete graph K9.svg|120px]]<BR>[[Complete graph]] K<sub>9</sub> |[[Image:Nonagon.svg|120px]]<BR>[[Enneagon]] {9/1} |[[Image:star polygon 9 2.png|120px]]<BR>Star polygon {9/2} |[[Image:Star figure 9-3.png|120px]]<BR>Star figure {9/3} |[[Image:star polygon 9 4.png|120px]]<BR>Star polygon {9/4} |} ==See also== * [[List of regular polytopes#Two Dimensions 2|List of regular star polygons]] * [[Enneagon]] [[Category:Enneagram]] [[fi:Enneagrammi]] [[cs:enneagram]] [[da:enneagram]] [[de:Enneagramm]] [[hu:Enneagramma]] [[id:enneagram]] [[nl:enneagram]] [[no:enneagram]] [[pl:enneagram]] [[pt:eneagrama]] [[sv:enneagram]]