Solution
= Solution
The listed points are precisely integer combinations of $a_1,a_2,a_3$ (the face-centred cubic lattice), as follows by sorting the parity classes of doubled Cartesian coordinates.
= Solution
The listed points are precisely integer combinations of $a_1,a_2,a_3$ (the face-centred cubic lattice), as follows by sorting the parity classes of doubled Cartesian coordinates.