#g2 f1 % point group to the space group of g.6.4
4	% generator
 -1 -1 -1 -1
  0  1  0  0
  0  0  1  0
  0  0  0  1
4	% generator
  1  0  1  1
  0  0  0 -1
  0  1  0  0
 -2 -1 -1 -1
4x0	% invariant form
 4
 2 2
 2 1 2
 2 1 1 2
% order of the group unknown