The poem's imagery helps to highlight the contrast between fleeting human experiences and the cold indifference of the universe.
In lines 9-10, for example, the speaker describes "the drenched grass / Smell" of their child's "sleeps." The sleeping child brings to mind the soothing scent of wet grass (perhaps after heavy rainfall). The lush imagery ties the child to the natural world; this scent is a distinctly earthy one and evokes freshness and vitality.
Similarly, the speaker describes their child's "gestures" as "[w]arm and human," marked by "pink light" that ultimately "[b]leed[s]" and "peel[s]" away. That warmth recalls the warmth of the human body, while the pinkness suggests the color of the child's flesh. The imagery of bleeding and peeling, meanwhile, creates a gruesome sensation of flesh being stripped away. Again, this imagery highlights the child's physicality, in turn reminding readers that the child's body will one day decay. By contrast, space is "cold" and "black," a place devoid of warmth, blood, flesh, and so forth.
Finally, the speaker compares the "gift" of moments with their child to snowflakes, "[s]ix sided, white," that descend on their "eyes," "lips," and "hair." Readers can envision the chilly "flakes" fluttering down onto the speaker like a gentle snowfall, only to immediately melt when coming into contact with the warmth of the speaker's skin. Again, the imagery foregrounds physicality; being human—having a warm body—means being unable to hold onto experiences.