"Mending Wall" by Robert Frost.

In the poem "Mending Wall" by Robert Frost, there are physical, moral and mental boundaries between the men. The wall between the men, acts as a physical boundary, dividing their property.
A language technique used in the poem is a simile.

Bringing a stone grasped firmly by the top

In each hand, like an old-stone savage armed.

The persona is comparing the traditional farmer to a perhistoric cave-man.

The use of visual imagery is used to describe the destruction of the wall.

That sends the frozen-ground-swell under it

And spills the upper boulder in the sun,

And makes gaps even two can pass abreast.