In the poem, 'The Road Not Taken', how does Robert Frost use poetic techniques to explore the concept of discovery?

Once one has made a full reading of the poem, it is clear that the primary poetic technique employed throughout the poem is the extended metaphor. An extended metaphor is an analogy that runs throughout the poem and in which the poet makes a comparison to the subject in the poem to something else.

The metaphor in this poem relates to the idea that life is seen as a journey. Frost compares his choice about the two roads he faces in the woods to the choices we make in life. Once a specific choice has been made, there is no turning back and one can only ponder about what the result would have been if one had made an alternative choice, just as the speaker does in the poem. 

In terms of the question regarding the concept of discovery, it is quite clear through the extended metaphor that on ones journey through life, one is faced with many alternatives. It is a matter of choice, and in our poem the speaker chose the road 'less travelled by' which, to him, has 'made all the difference.' We are not quite clear whether the difference was good or bad, since the speaker does not tell us.

Thus poet leaves us with a very clever conundrum in the end, forcing us to wonder and make a choice ourselves about whether the speaker's choice had been a good one or not. In this, he once again emphasises the central theme of the poem: that our journey of discovery is about making choices. The answer to the conundrum has encouraged much debate over the years, one which is still ongoing.

In the first stanza, the poet uses repetition. The poet repeats 'and' at the beginning of three consecutive lines, from line three to line four. 'And' is repeated in lines 7, 11 and in the last line. The repetition reflects the speaker's uncertainty, which is especially accentuated in this instance. In the other lines 'and' is used more as a connective but reminds the reader of its use in lines three to four, which once again, d its importance.

The rhyme scheme follows the same pattern throughout the poem: abaab; cdccd; efeef; ghggh. This binds the poem and underscores the extended metaphor and the central theme of the poem. Furthermore, each line consists of nine syllables (except line 15, which has ten) which gives the poem a regular, flowing and steady rhythm. Because this rhythm is broken only once in line fifteen, it gives the poem continuity, affirming once again the continuation of a journey. 

The break in rhythm in line fifteen creates a pause, emphasising not only the  speaker's uncertainty - further informed by the word 'doubted' - but also tells us that the speaker realises that once the choice has been made, there is little chance of coming back.