import pyscal.crystal_structures as pcs
import pyscal.core as pc
from pyscal.atoms import Atoms
atoms, box = pcs.make_crystal(structure="fcc", repetitions=2)
at = Atoms()
at.from_dict(atoms)
at.mask.primary
[False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False]