How does Giuseppe Ungaretti use imagery in Variations on Nothing?

In "Variations on Nothing," as in many of Ungaretti's works, the poet concentrates on a single, simple idea and fleshes it out with powerful, descriptive words. The subject in this poem is the fleeting time of human life and the endurance of nonhuman earthly objects. An hourglass may depend on a person's hand to turn it over in order to repeat its measurement of time, but when the hand is gone, the object continues to measure the passing of time. While the overall message is philosophical and obviously abstract, the poet conveys this message with precise images of tangible objects and real-life moments that are both striking and accessible.