My interpretation of this is that the author was hoping for something futile - they 'grew a flower' (put effort or hopes toward) that can't be bloomed (is pointless or futile, will not produce anything) that can't come true (their effort/hope is just a hopeful dream). Basically, the author hoped for something that was not possible.
Answer:
value
Explanation:
Value is how artists use light and darkness in their artwork.
The artist is using the appeal of pathos (emotional response). They play on the viewers association of the sky with endlessness, as it is often described as such. Additionally, most people associate the sky with birds which are used as mascots which hold value for freedom, like America's bald eagle. Lastly, people have an involuntary reaction to positive stimulus by smiling.