Joined pentachoron

The joined pentachoron, also known as the triangular-bipyramidal decachoron or tibbid, is a convex isochoric polychoron with 10 triangular bipyramids as cells. It can be obtained as the dual of the rectified pentachoron.

It can also be obtained as the convex hull of 2 dually-oriented pentachora, where one has edge length $$\frac232 = 1.5$$ times that of the other.

The ratio between the longest and shortest edges is 1:1.5. Each face is an isosceles triangle that uses one long and two short edges.

Isogonal derivatives
Substitution by vertices of these following elements will produce these convex isogonal polychora:
 * Triangular bipyramid (30): Rectified pentachoron
 * Isosceles triangle (30): Semi-uniform small rhombated pentachoron
 * Edge (10): Rectified pentachoron
 * Edge (20): Semi-uniform small prismatodecachoron
 * Vertex (5): Pentachoron
 * Vertex (5): Pentachoron