Re: face centered cubic ( cubic close pack) and simple cubic

I've put into the Menger sponge program  several space group unit cells 
stuctures as vertices :

1) cubic close pack/ face centered cubic ( NaCl and about half the metals)
2) zinc blend ( ZnS  and carbon, Si, Ge...)
3) Body centered cubic  ( some metals )
4) Hexagonal close pack  ( Zn, Zr, Ti... other half of the metals)

What I discovered late yesterday
( which should not have come as a surprise)
if you use ratio 2 instead of Menger 3,
you get a crystal build up instead of a fractal.
That is the space group unit cells behave just like a space fill
with their voids included. (So much for
tiling units with voids not being tiles.)
It is interesting that this result implies that crystal formation is
a fractal  self-similar process.