Possible points of comparison between fog and duckweed. comparison between presence of fog(in cripple's songs and englishman's paintings) and duckweed(flowers).
This is a tough question, but you might consider that both of these natural items rely on wind or ripples in the water to move them about. Both fog and duckweed are unable to control themselves or what happens to them. They must be controlled by outside forces.
Hope this helps!
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