The use of repetition and parallelism has a profound impact on the mood of the poem. To illustrate, the lines “anger, anger against the dying of the light” and “Do not go gently into that good night” are repeated throughout the poem, where the emphasis and urgency of the poet's tone is clearly demonstrated. It is used to further emphasize Thomas' emotional and moving plea to his father to embrace life to the end. Furthermore, the repetition of “anger” also increases the intensity of the warnings. Secondly, Dylan describes four types of men to his father through parallelism. The use of "wise men" is a rebuke to the father's willingness to accept death as definitive. Although the “wise men” see death as salvation, as implied in “darkness is right,” they would not succumb to death because “they had not forked any lightning.” It indicates that one should not simply die without leaving a “dent in the universe”. “Good men” cry with their dying breath for the loss of their “fragile actions,” where action connotes both the physical body and benevolence. The “wild men” full of life and song try to catch the sun as if life were one long day from dawn to dying dusk, but they realize the prodigal nature too late. They too grieve for their actions and struggle against death. Thomas concludes his repetitive demonstration of ideals with the “Grave men,” who according to Thomas, even in their final moments, can “blaze like meteors and be gay.” Thomas imparts this final simile to represent the satisfaction one feels when looking back at one's life, preventing them from feeling the desperation and futility that Thomas wants his father to move away from. Thomas's use of diction also plays a decisive role in the poem. First, the predominant part... in the center of the card... further emphasizes the desire to live. Finally, “there on the sad height” used in the last stanza uses a biblical reference. The sad hill could very likely represent the Valley of Despair that separates the human world from the metaphysical one. Dylan describes his father as being on the edge of the human world to make the atmosphere more solemn and somber and to emphasize the daunting prospect of his father's recovery. Don't Go Gentle Into That Good Night is a very subtle and intricate poem that focuses on dying gloriously while avoiding death. Throughout the poem, Dylan Thomas uses powerful tools to create a melancholic yet urgent tone as we witness the passing of his father. To quote Mary Alice Young, “Death is nothing but a promise made to each of us at birth, but before the promise is kept,” each of us should live life to the fullest..