Example: 'C 1 2 1'  (instead of C 2)
           'P 1 2 1'  (instead of P 2)
           'P 1 21 1' (instead of P 21)
           'P 1 1 21' (instead of P 21 -unique C axis)
           'H 3'      (instead of R 3   -hexagonal)
           'H 3 2'    (instead of R 3 2 -hexagonal)