This animation visualizes how the chestahedron comes into being when a tetrahedron is “opened up” like a flower. As the tetrahedron opens, it becomes the chestahedron, finally becoming a stellated octahedron. The stellated octahedron fits exactly within a larger tetrahedron that is exactly double the size of the original tetrahedron. The chestahedron then comes out of the tetrahedron and spins into the bell shape. The first animation should automatically play when loaded. Click on the other two for different views.

Camera view #1:

Camera view #2:

Camera view #3:

This sequence was also physically constructed. Click the images for larger views. Notice how the small yellow tetrahedron’s top point moves upward in four successive stages, each of which is constructed as a separate model. The chestahedron form arises when the small yellow tetrahedron’s top point has moved to the midpoint between its original position and the top of the large tetrahedron.