Acronym ..., sishi || fix Name (degenerate) sishi atop fix,(degenerate) sishi antiprism,(degenerate) fix antiprism Circumradius ∞   i.e. flat in euclidean space Confer general polytopal classes: decomposition

It either can be thought of as a degenerate 5D segmentotope with zero height, or as a 4D euclidean decomposition of the larger base into smaller bits.

As abstract polytope sishi || fix is isomorphic to gaghi || gofix, thereby replacing pentagrams by pentagons, resp. sissid by gad, stappy by peppy, and ike by gike, resp. sishi by gaghi, sissidpy by gadpy, stasc by pesc, ikepy by gikepy, and fix by gofix.

Incidence matrix according to Dynkin symbol

```xo5/2oo5oo3ox&#x   → height = 0
(sishi || fix)

o.5/2o.5o.3o.    | 120   * |   20   12   0 |  30   60   30    0 |  12   60   60   20   0 | 1  12  30   20   1 0
.o5/2.o5.o3.o    |   * 120 ♦    0   12  12 |   0   30   60   30 |   0   12   60   60  12 | 0   1  12   30  12 1
-----------------+---------+---------------+--------------------+------------------------+---------------------
x.   .. .. ..    |   2   0 | 1200    *   * |   3    3    0    0 |   3    6    3    0   0 | 1   3   3    1   0 0
oo5/2oo5oo3oo&#x |   1   1 |    * 1440   * |   0    5    5    0 |   0    5   10    5   0 | 0   1   5    5   1 0
..   .. .. .x    |   0   2 |    *    * 720 |   0    0    5    5 |   0    0    5   10   5 | 0   0   1    5   5 1
-----------------+---------+---------------+--------------------+------------------------+---------------------
x.5/2o. .. ..    |   5   0 |    5    0   0 | 720    *    *    * |   2    2    0    0   0 | 1   2   1    0   0 0
xo   .. .. ..&#x |   2   1 |    1    2   0 |   * 3600    *    * |   0    2    2    0   0 | 0   1   2    1   0 0
..   .. .. ox&#x |   1   2 |    0    2   1 |   *    * 3600    * |   0    0    2    2   0 | 0   0   1    2   1 0
..   .. .o3.x    |   0   3 |    0    0   3 |   *    *    * 1200 |   0    0    0    2   2 | 0   0   0    1   2 1
-----------------+---------+---------------+--------------------+------------------------+---------------------
x.5/2o.5o. ..    ♦  12   0 |   30    0   0 |  12    0    0    0 | 120    *    *    *   * | 1   1   0    0   0 0
xo5/2oo .. ..&#x ♦   5   1 |    5    5   0 |   1    5    0    0 |   * 1440    *    *   * | 0   1   1    0   0 0
xo   .. .. ox&#x ♦   2   2 |    1    4   1 |   0    2    2    0 |   *    * 3600    *   * | 0   0   1    1   0 0
..   .. oo3ox&#x ♦   1   3 |    0    3   3 |   0    0    3    1 |   *    *    * 2400   * | 0   0   0    1   1 0
..   .o5.o3.x    ♦   0  12 |    0    0  30 |   0    0    0   20 |   *    *    *    * 120 | 0   0   0    0   1 1
-----------------+---------+---------------+--------------------+------------------------+---------------------
x.5/2o.5o.3o.    ♦ 120   0 | 1200    0   0 | 720    0    0    0 | 120    0    0    0   0 | 1   *   *    *   * *
xo5/2oo5oo ..&#x ♦  12   1 |   30   12   0 |  12   30    0    0 |   1   12    0    0   0 | * 120   *    *   * *
xo5/2oo .. ox&#x ♦   5   2 |    5   10   1 |   1   10    5    0 |   0    2    5    0   0 | *   * 720    *   * *
xo   .. oo3ox&#x ♦   2   3 |    1    6   3 |   0    3    6    1 |   0    0    3    2   0 | *   *   * 1200   * *
..   oo5oo3ox&#x ♦   1  12 |    0   12  30 |   0    0   30   20 |   0    0    0   20   1 | *   *   *    * 120 *
.o5/2.o5.o3.x    ♦   0 120 |    0    0 720 |   0    0    0 1200 |   0    0    0    0 120 | *   *   *    *   * 1
```