Analyze and provide an in-depth analysis of Seamus Heaney's poem "Follower." What are key ideas, literary features, and literary techniques used?

"Follower," by Seamus Heaney, is a poem comprising six stanzas of four lines each. It is written with an ABAB rhyme scheme. The conversational rhythm of the poem is in keeping with its theme: an anecdote, it concerns the speaker's father laboring with a horse plough while the speaker himself "stumbled in his hob-nailed wake." The rhythm of the poem, regular and cohesive, echoes the onward motion of the plough.
In the first stanza of the poem, Heaney uses figurative language (a simile) to describe how his father, "shoulders globed like a full sail," was once almost part of the machinery of his horse-plough, his "clicking tongue" the instrument that drove the horse. He was "an expert": Heaney lends support to this claim by following it up with expert language specific to the activity: "the bright steel-pointed sock" and "the headrig." The precision and accuracy of the father's work, how he "mapped" "exactly" the "angled" ground, is contrasted to the son, who "stumbled" and "fell," supported sometimes on his father's back, "dipping and rising to his plod." The dual meaning here is evident: the son moved literally up and down with his father's steps but also felt metaphorically buoyed up by him in moments of weakness and was inspired to "follow" in his father's "broad shadow." Clearly, the shadow cast by the father's achievements is long and has followed the son all his life.
In the final stanza of the poem, this idea is turned on its head, the shift in angle very stark and jolting the reader out of the rhythm of the rest of the poem, which has continually focused upon the reliable act of ploughing. Now, the speaker says, "it is my father who keeps stumbling/Behind me, and will not go away." We could interpret this in several ways, but the most straightforward reading is probably that the speaker feels haunted or pursued by the idea of his father, no longer an upright "expert" guiding the plough, but rather a ghost ("stumbling" suggests the shuffling motions of a zombie, figuratively, on one hand, and an elderly person on the other). Perhaps the achievements of the father seem to dog the son's steps because he feels inadequate; equally, we could read this as an indication that the father, who was once so revered by the son, did not live up to those expectations once the speaker was old enough to move through life without "stumbling" himself. The role reversal (note the uses of "stumble") in the poem might also relate to the common theme of late life as a second childhood, with the son who was once supported by his father now required to look after him, the father figuratively "stumbling" behind him in the sense that he is a responsibility the son cannot escape or shake from his thoughts.