Acronym	tricu, J3
Name	triangular cupola, half of cuboctahedron
	© ©
Circumradius	1
Vertex figures	[(3,4)2], [3,4,6]
Volume	5 sqrt(2)/6 = 1.178511
General of army	(is itself convex)
Colonel of regiment	(is itself locally convex)
Dihedral angles	between {3} and {4}:   arccos[-1/sqrt(3)] = 125.264390° between {3} and {6}:   arccos(1/3) = 70.528779° between {4} and {6}:   arccos[1/sqrt(3)] = 54.735610°
Face vector	9, 15, 8
Confer	general cupolae: n/d-cu   uniform relative: co   related Johnson solids: tobcu   etigybcu   etobcu   general polytopal classes: Johnson solids   segmentohedra   lace simplices
External links

Tricu is an edge-faceting of co, in fact it uses triangles and squares of it and an equatorial hexagon.

Incidence matrix according to Dynkin symbol

xx3ox&#x   → height = sqrt(2/3) = 0.816497
({3} || {6})

o.3o.    | 3 * | 2 2 0 0 | 1 2 1 0
.o3.o    | * 6 | 0 1 1 1 | 0 1 1 1
---------+-----+---------+--------
x. ..    | 2 0 | 3 * * * | 1 1 0 0
oo3oo&#x | 1 1 | * 6 * * | 0 1 1 0
.x ..    | 0 2 | * * 3 * | 0 1 0 1
.. .x    | 0 2 | * * * 3 | 0 0 1 1
---------+-----+---------+--------
x.3o.    | 3 0 | 3 0 0 0 | 1 * * *
xx ..&#x | 2 2 | 1 2 1 0 | * 3 * *
.. ox&#x | 1 2 | 0 2 0 1 | * * 3 *
.x3.x    | 0 6 | 0 0 3 3 | * * * 1

so6ox&#x   → height = sqrt(2/3) = 0.816497
({3} || {6})

demi( o.6o.    ) | 3 * | 2 2 0 0 | 1 1 0 2
      .o6.o      | * 6 | 0 1 1 1 | 0 1 1 1
-----------------+-----+---------+--------
sefa( s.6o.    ) | 2 0 | 3 * * * | 1 0 0 1
demi( oo6oo&#x ) | 1 1 | * 6 * * | 0 1 0 1
demi( .. .x    ) | 0 2 | * * 3 * | 0 0 1 1
demi( .. .x    ) | 0 2 | * * * 3 | 0 1 1 0
-----------------+-----+---------+--------
      s.6o.      | 3 0 | 3 0 0 0 | 1 * * *
demi( .. ox&#x ) | 1 2 | 0 2 0 1 | * 3 * *
      .o6.x      | 0 6 | 0 0 3 3 | * * 1 *
sefa( so6ox&#x ) | 2 2 | 1 2 1 0 | * * * 3

starting figure: xo6ox&#x