Reflect, Reflection
The sun in the center of the sky gives off its light, which reflects off of everything around it.
Look around you, everything you see is reflecting the light of the sun. Unless it's night time, then the tiny sun in the center of your lightbulb is creating the light that reflects there.
えい
うつ, は
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This reflected light is important for acorns (えい), in particular. Without light reflecting off everything, the sun's light would never make it down to the ground where they've fallen. They would never grow into trees. And we'd all suffocate.
Picture the light of the sun reflecting off a single acorn on the forest floor. So much symbolism!