The rhyme scheme of this poem by Frost, is ABA AB. The rhyme scheme is the same throughout the poem. The narrator takes the reader back to a time when he is almost at a stand still. He has to choose between to different paths and he is not sure which one to take. In the first two stanzas of this poem, the narrator describes both paths to the reader.
He comes to the conclusion that there isn't much difference between the two paths. In the third stanza he decides to take the second path and keep "the first for another day." However he states that he doubts that he will ever come back. In the final stanza the narrator tells the reader that choosing the second path has made all of the difference. Although he says that it has made all the difference the reader knows that this is probably not true. In this poem the narrator is actually comparing the choice he had to make between the two paths to a choice he has had to make in real life. Although the reader never really knows what that choice is, it was an important choice because as he states at the end that it has made a difference.
The reader knows that choosing one path in the poem over another has not really made the "difference" however the choice he made in real life may have. He makes it clear in the last stanza in the line, "I shall be telling this with a sigh, Somewhere ages and ages hence:" that when he looks back he will not regret his decision and know that his choice was pleasing. Although it seems as though Frost is talking about the path he chose, the title tells us different - The Road Not Taken. The narrator never says that he regrets his decision yet at the same time the title of the poem refers to the road he didn't take. Years later the narrator wants to be able to reaffirm his decision to take the second road, however he doesn't think that he will be able to.
This again is where the reader would question the line "And that has made all the difference," because in reality it hasn't. The narrator uses this poem as a metaphor for real life. He suggests that although we may think that we have made the right decision we may decide later that we have not. The narrator also suggests that we will always wonder what taking "the other road" may have done for you. Frost, Robert. The Road Not Taken.