2-2'

#g1 f2 z2 n1 c2
  2x  2
  0  1
 -1  1

  2x  2
  2 -1
 -1  2

  2x  2
  0  1
 -1  0
2	% zentr
 1 -1
 1  0
2d0	%  zentr
-1
2x2  % normalizer
0 1
1 0
2	% cen
 1 -1
 1  0
2d0	%  cen
-1
2^1 * 3^1 = 6 %order of the group