Sewing imagery conveys her nervousness and physical feelings of anxiety.
“tucks, darts, pleats”
Simile shows the world from the son’s perspective - makes it sound exciting and full of precious experiences
“the world overflowing/ like a treasure chest”
Symbolises her son leaving
“released a song bird from its cage”
Strong visual image hints against the sky, at her wish for his safety
“leaned against it like a wishbone”
Alliteration echoes the way she’s straining to hear him. Links leaving to join the army with leaving to go to school
“hoping to hear. Your playground voice catching on the wind”