'none': # 1, m
'2': # 2, 2/m, mm2, -4
'222': # 222, mmm, -42m
'4': # 4, 4/m
'422': # 422, 4/mmm
'3': # 3, 3m1, 31m, -3, -6
'32': # 321, 312, -31m, -3m1, -6m2
'6': # 6, 6/m, 6mm
'622': # 622, 6/mmm
'23': # 23, -43m,  m-3
'432': # 432, m-3m