The other side of the mountain takes the mountains and the sea as images, expressing a belief and a philosophy, and enlightening people that to realize lofty ideals, they must persevere and persist in their struggle. The two symbolic relative images of "mountain" and "sea" transform the poet's philosophical perception into a concrete and practical process of continuous pursuit of life.
The first layer: the writer's yearning and pursuit of the sea in childhood, not the disappointment and depression after the result.
The second layer: the writer's feelings of crossing mountains and mountains to see the sea as an adult, as well as his firm belief in ideals.