|
902.31
As you go from one sphere-foldable great-circle set
to another in the
hierarchy of spinnable symmetries (the 3-, 4-, 6-, 12-sets
of the vector equilibrium's 25-
great-circle group and the 6-, 10-, 15-sets of the icosahedron's
31-great-circle group), the
central angles of one often become the surface angles
of the next-higher-numbered, more
complex, great-circle set while simultaneously some
(but not all) of the surface angles
become the respective next sphere's central angles.
A triangle on the surface of the
icosahedron folds itself up, becomes a tetrahedron,
and plunges deeply down into the
congruent central angles' void of the icosahedron (see
Sec.
905.47
).
|