نجمة تساعية

نجمة تساعية
Enneagram
Enneagon stellations.png
Enneagrams shown as sequential stellations

في الهندسة، النجمة التساعية enneagram nonagram, nonangle, or enneagon، هي مضلع ثماني الرؤوس. [1]

The word 'enneagram' combines the numeral prefix ennea- with the Greek suffix -gram. The gram suffix derives from γραμμῆς (grammēs) meaning a line.[2]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

النجمة التساعية الاعتيادية

A regular enneagram is a 9-sided star polygon. It is constructed using the same points as the regular enneagon, but the points are connected in fixed steps. Two forms of regular enneagram exist:

  • One form connects every second point and is represented by the Schläfli symbol {9/2}.
  • The other form connects every fourth point and is represented by the Schläfli symbol {9/4}.

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.[3][4] (If the triangles are alternately interlaced, this results in a Brunnian link.) This star figure is sometimes known as the star of Goliath, after {6/2} or 2{3}, the star of David.[5]

Compound Regular star Regular
compound
Regular star
8-simplex t0.svg
Complete graph K9
Regular star polygon 9-2.svg
{9/2}
Regular star figure 3(3,1).svg
{9/3} or 3{3}
Regular star polygon 9-4.svg
{9/4}


نجمات تساعية أخرى

Enneagram 9-4 icosahedral.svg
The final stellation of the icosahedron has 2-isogonal enneagram faces. It is a 9/4 wound star polyhedron, but the vertices are not equally spaced.
Enneagram.png
The Fourth Way teachings and the Enneagram of Personality use an irregular enneagram consisting of an equilateral triangle and an irregular hexagram based on 142857.
Bahai star.svg
The Bahá'í nine-pointed star
Nine-point star (fixed width).svg
A 9/3 enneagram

The nine-pointed star or enneagram can also symbolize the nine gifts or fruits of the Holy Spirit.[6]

في الثقافة العامة

  • The heavy metal band Slipknot previously used the {9/3} star figure enneagram[7] and currently uses the {9/4} polygon as a symbol. The prior figure can be seen on the cover of All Hope Is Gone.

انظر أيضا

For the use of the enneagram in other contexts, see:

المصادر

  1. ^ "Between a square rock and a hard pentagon: Fractional polygons". 28 September 2017.
  2. ^ γραμμή, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus.
  3. ^ Grünbaum, B. and G. C. Shephard; Tilings and Patterns, New York: W. H. Freeman & Co., (1987), ISBN 0-7167-1193-1.
  4. ^ 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.
  5. ^ Weisstein, Eric W. "Nonagram". mathworld.wolfram.com.
  6. ^ Our Christian Symbols by Friedrich Rest (1954), ISBN 0-8298-0099-9, page 13.
  7. ^ "slipknot". eBay.

وصلات خارجية

الكلمات الدالة: