Bilunabirotunda (EntityTopic, 14)

(Difference between revisions)

Revision as of 22:10, 2 March 2014

The bilunabirotunda is the 91st Johnson solid, J91. It suddenly became important when the castellated rhodoperihedral prism was discovered.

The following coordinates give an origin-centered bilunabirotunda with edge length 2:

<±1, 0, ±φ²>

<±φ, ±1, ±1>

<0, ±φ, 0>

where φ=(1+√5)/2 is the Golden Ratio.

total edge length = 26l
surface area = (2 + 2√3 + √(25+10√5)) · l²
volume = ¹∕₆ · (4φ² + 5φ) · l³

Notable Trishapes
Regular:	tetrahedron • cube • octahedron • dodecahedron • icosahedron
Direct truncates:	tetrahedral truncate • cubic truncate • octahedral truncate • dodecahedral truncate • icosahedral truncate
Mesotruncates:	stauromesohedron • stauroperihedron • stauropantohedron • rhodomesohedron • rhodoperihedron • rhodopantohedron
Snubs:	snub staurohedron • snub rhodohedron
Curved:	sphere • torus • cylinder • cone • frustum • crind

@@ Line 4: / Line 4: @@
 | image=<[#embed [hash E8W2T39SHBA6TBWV9MR9AY87GA] [width 160]]>
 | elements=14, 26, 14
+| sym=[[Biprismatic symmetry|D<sub>2h</sub>]]
 | genus=0
 | extra={{STS Polytope
 | flayout={{FLD|a2tr|ti|asrtm|ditm|aqtm|editm|atlsl|cr}}
+| bowers=bilbiro
 }}}}
 The '''bilunabirotunda''' is the 91st [[Johnson solid]], J91. It suddenly became important when the [[castellated rhodoperihedral prism]] was discovered.