Cantitruncated Pentachoron (307-Grip)
The cantitruncated pentachoron is number 307 in the list of uniform polychora
with the abbreviated name "grip". It has 20 cells:
5 truncated octahedra (hidden),
5 truncated tetrahedra (green) and
10 triangular prisms (red). This model represents a perspective projection of
the 4D polytope into 3D space, with the truncated octahedral cells hidden to
reveal the internal structure.
See this tutorial for some comments on
obtaining nets for building paper models of 4D polytopes.
Here are the different cells involved, which were then glued together
to complete the model. You need 4 of each of the red parts, 4 of the
bigger green part, and 1 of the smaller green part at the centre.
Glue them together from the inside out.