Acronym addasi
Name altered disnub icosahedron,
compound of 20 oct (but not dasi)
 
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Circumradius 1/sqrt(2) = 0.707107
Inradius 1/sqrt(6) = 0.408248
Vertex figure [34]
Dihedral angles
(at margins)
  • between {3} and {3}:   arccos(-1/3) = 109.471221°
Confer
related compounds:
se   si   gissi   dasi  
External
links
hedrondude   wikipedia  

This compound has rotational freedom. It can be obtained at φ = 0° by 2 coincident si, rotating either of the (then) coincident oct, thought of as triagular antiprisms within an ike, in opposite directions around those axes. At φ = 60° this compound again comes to be 2 coincident gissi. Inbetween there are 2 further singular positions: One, where 4 (different oriented oct coincide each, resulting in a 4-fold cover of se. The other one, when vertices coincide by pairs, resulting in a static compound of 20 oct, called dasi.


Incidence matrix

120 |   2   2 |   3  1 ||  1
----+---------+--------++---
  2 | 120   * |   1  1 ||  1
  2 |   * 120 |   2  0 ||  1
----+---------+--------++---
  3 |   1   2 | 120  * ||  1
  3 |   3   0 |   * 40 ||  1
----+---------+--------++---
 6 |   6   6 |   6  2 || 20

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