Hello. You didn't attach the poem or even say the title of the poem, which makes it impossible for me to answer your question accurately, but I will help you as much as I can by showing you how to find your answer.
The simile makes comparisons between elements that have different contexts, but that has a characteristic between both that can be related creating a new meaning and concept between one of these elements. In other words, the simile aims to show a concept shared between two different elements. This type of comparison, within a poem, can create a message pattern, where the entire poem is aimed at maintaining the tone that the simile projected during the comparison.
An example of this can be seen in the phrase "My heart fell in life like a star wounded by a hunter's arrow," where the hunter's heart and arrow are different elements, but promote the feeling of pain and sadness when compared.
A singular ,common,concrete noun; a word for a measurement.
The main theme that a reader can derive is that even though life can be hard, we need hope for a better tomorrow.
