The following verifies the Kasteleyn's formula (Eq. (15) in his classic pape\
    r), for symbolic z for all even n from 2 to 6

                          When n=,, 2, the formula is

                                      true

                          When n=,, 4, the formula is

                                      true

                          When n=,, 6, the formula is

                                      true