Acronym stiscu
Name pentagrammic cuploid,
star semicupola
 
 ©
 ©
embedding of stiscu within sidtid
Circumradius sqrt(3)/2 = 0.866025
Vertex figures [3,4,5/2,4], [3,4,3/2,4/3]/0
Confer
more general:
n/d-cu  
uniform relative:
sidtid  
Grünbaumian relatives:
stacu  
blends:
toroidal bistiscu  
general polytopal classes:
segmentohedra  
External
links
mcneill

Stiscu is an edge-faceting of sidtid, in fact it uses triangles and pentagrams of it and squares of rhom, the inscribed compound of 5 cube.

As a cuploid it has a pseudo bottom face. That one is the withdrawn {10/2} of the corresponding cupola. By that withdrawel the top base becomes a membran, as the central part becomes accessible from the outside at both sides.

As abstract polytope stiscu is isomorphic to rapescu, thereby replacing the (prograde) pentagram by a retrograde pentagon, while pseudo pentagon would become a pseudo pentagram.


Incidence matrix according to Dynkin symbol

reduced(xx5/2ox&#x by x5/2x)   → height = sqrt((5+sqrt(5))/10) = 0.850651
({5/2} || pseudo {10/2})

o.5/2o.             | 5 * | 2  2 0 | 1 2 1
.o5/2.o             | * 5 | 0  2 2 | 0 2 2
--------------------+-----+--------+------
x.   ..             | 2 0 | 5  * * | 1 1 0
oo5/2oo&#x          | 1 1 | * 10 * | 0 1 1
.x   ..  &  ..   .x | 0 2 | *  * 5 | 0 1 1  (those edges get identified)
--------------------+-----+--------+------
x.5/2o.             | 5 0 | 5  0 0 | 1 * *
xx   ..&#x          | 2 2 | 1  2 1 | * 5 *
..   ox&#x          | 1 2 | 0  2 1 | * * 5

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