#g2 f1 % point group to the space group of g.4.2
4	% generator
 -1 0 0 -1
  0 1 0  0
  0 0 1  0
  0 0 0  1
4	% generator
  1 0 -1  0
  1 0  0  1
  1 1  0  1
 -2 0  0 -1
4x0	% invariant form
 2
 0 2
 0 0 2
 1 1 1 2
% order of the group unknown
