The perpendicular rhombs described above in connection with the Coupler and rhombic dodecahedron are given animated treatment as a part of a multi-part Youtube series. Director: K. Urner Screenwriter: D. Koski.
In this series, the idea of a Rhombic Book, two triangular book covers symmetrical about a spine, and a page flapping back and forth, another below at 180 degrees (optional), is used to introduce three tetrahedrons:
(a) the one comprised of a left book cover and the page (b) the one comprised of a right book cover and the page (c) an "inadvertent one" comprised of the two varying lengths at 90 degrees and opposite one another, other lengths same as rhomb's.
(a) + (b) + (c) assemble a topological IVM in a way described in the vids.
Also (a), (b) and (c) are all of same volume as one another, though as the page revolves they cycle through a minimum / maximum.
These concepts help reinforce / anchor some of the other animations and demos we've been touring.