Manipulating a flexible closed mesh/polyhedra

Trying to model and then have control over the range of motion of a flexible polyhedron. The engine appears to think the closed mesh is rigid and won’t let me flex it without deforming. Any thoughts very much appreciated!! Kangaroo_SS.3dm (3.3 MB)Kangaroo 2 (10.7 KB) (11.9 KB)
I’d set it up like this. The grab component lets you manipulate it by dragging points in Rhino.
This polyhedron doesn’t appear to be flexible though. Is it supposed to be Steffen’s polyhedron?
I think if it is the edge lengths need adjusting.

I see. Thank you!! It is meant to Steffen… but maybe I messed up constructing the net. Will go back and reconfigure and let you know. Thanks again in the mean time!