Acronym	didpy, pt || did
Name	(degenerate) did pyramid
Segmentochoron display
Circumradius	∞   i.e. flat in euclidean space
Dihedral angles	at {3} between peppy and stappy:   180° at {5} between did and peppy:   0° at {5/2} between did and stappy:   0°
Face vector	31, 90, 84, 25
Confer	general polytopal classes: decomposition

It either can be thought of as a degenerate 4D segmentotope with zero height, or as a 3D euclidean decomposition of the larger base into smaller bits.

Incidence matrix according to Dynkin symbol

oo5ox5/2oo&#x   → height = 0
(pt || did)

o.5o.5/2o.    | 1  * ♦ 30  0 | 60  0  0 | 12 12 0
.o5.o5/2.o    | * 30 |  1  4 |  4  2  2 |  2  2 1
--------------+------+-------+----------+--------
oo5oo5/2oo&#x | 1  1 | 30  * |  4  0  0 |  2  2 0
.. .x   ..    | 0  2 |  * 60 |  1  1  1 |  1  1 1
--------------+------+-------+----------+--------
.. ox   ..&#x | 1  2 |  2  1 | 60  *  * |  1  1 0
.o5.x   ..    | 0  5 |  0  5 |  * 12  * |  1  0 1
.. .x5/2.o    | 0  5 |  0  5 |  *  * 12 |  0  1 1
--------------+------+-------+----------+--------
oo5ox   ..&#x ♦ 1  5 |  5  5 |  5  1  0 | 12  * *
.. ox5/2oo&#x ♦ 1  5 |  5  5 |  5  0  1 |  * 12 *
.o5.x5/2.o    ♦ 0 30 |  0 60 |  0 12 12 |  *  * 1