 format  1  0
Bravais   = basis (group p4mm) 
2         = dim
4         = # symmetries

 1
    1.0   0.0     0.0
    0.0   1.0     0.0

 2 (2 0,0) 
   -1.0   0.0     0.0
    0.0  -1.0     0.0

 3 (m 0,y)
   -1.0   0.0     0.0
    0.0   1.0     0.0

 4 (4+ 0,0) 
    0.0   1.0     0.0
   -1.0   0.0     0.0 
