format 1 0
Bravais   = basis  (p1g1, 2-d space group 6)
2         = dim
2         = # symmetries

 1
    1.0  0.0    0.0
    0.0  1.0    0.0

 2 (b 0,y)
   -1.0  0.0    0.0
    0.0  1.0    0.5
