What is the poetic form of this excerpt from Robert Frost's "Mending Wall"?

Bringing a stone grasped firmly by the top
In each hand, like an old-stone savage armed.
He moves in darkness as it seems to me,
Not of woods only and the shade of trees.
He will not go behind his father's saying,
And he likes having thought of it so well

The statement isn't presented thoroughly enough to answer .

The main themes of the play are: fate and free will with the inevitability of oracular predictions is a theme that often occurs in greek tragedies the conflict between the individual and the state similar to that in sophocles’ “antigone” and   people’s willingness to ignore painful truths both oedipus and jocasta clutch at unlikely details in order to avoiding facing up to the inceasingly apparent truth and sight and blindness the irony that the blind seer tiresius can actually “see” more clearly than the supposedly clear-eyed oedipus, who is in reality blind to the truth about his origins and his inadvertent crimes.