In Dylan Thomas's poetry, he refers to an inexorable, amoral force that exists within the universe. This force exists in all things, yet cannot be manipulated. His first collection, 18 Poems, serves as the premier source for defining and understanding the existence of this force. Two poems in particular, "A Process in the Weather of the Heart" and "The Force that Through the Green Fuse Drives the Flower," provide the most comprehensive examination of the force. However, his idea of the force is not confined to his poetry. During the last years of his life, he completed a play titled Under Mile Wood, which explores the treatment of the force. Within the play Thomas presents life as it exists in the small, seaside town of Llareggub. The town and its inhabitants are subject to the force, which results in the characters' unique eccentricities.