What is a detailed analysis of Elizabeth Jennings's "Poem in Winter" in terms of language, structure, tone, imagery, themes, and symbols?

In twentieth-century British poet Elizabeth Jennings's "Poem in Winter," the persona, or poem's speaker, contemplates how children understand the world. The children look forward to playing in the snow, and when the snow finally arrives, they think that the snow came only because they wished for it. The persona then concludes that believing the world is shaped by one's own desires is better than "hiding in the mind's corner as we do" (14).
The poem's mystical language reveals its central theme to be mystical modes of understanding the world. The persona says the children look for "auguries" and "omens" and place "their image" in the snowdrifts, and she concludes that it's "better to believe" (2, 3, 9, 11-12). Through these religious phrases, the persona explores our relationship to the world. Is it in fact, like she says, better to think that our surroundings are "created by a wish, a shaping hand," or our own desires, than to "hide in the mind's corner"? Or is it better to realize through our use of reason that we really have no control over our environment? (12-13, 14). She calls the former a "wise illusion"; with this paradoxical phrase, the persona suggests that the former notion is more sensible—but a lie (15).
As the poem progresses, its tone shifts from upbeat to dispirited. It begins happily, with children looking forward to the wintertime. The next few lines, however, are more downcast: the persona repeats "not" three times and emphasizes sulky words such as "settled," "slow," "falling," and "lie" (3-5). The poem's tone descends further as the persona watches the children from "behind a pane of glass," or from inside her own home (7). With her concluding two lines, the persona suggests that adults are unable to enjoy the world as children do; we live "as though there were no world, no fall of snow" (15). The poem then reproduces our loss of fantastical thought that occurs through aging by shifting the poem's tone from initially optimistic to ultimately depressing.
Snowflakes are the poem's prominent image. Since snowflakes are beautiful but eventually melt, they symbolize our initial conceptions of the world; in childhood we have the wonderful idea that the world is meant for us, but as we grow up, we learn that this actually isn't the case.
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