How does Eiji Yoshikawa use imagery in Musashi?

Imagery:

"At Fushimi alone, nearly a thousand laborers were engaged in extending the stone battlements, with the incidental result that the town around the castle experienced a sudden influx of peddlers, prostitutes and horseflies—all symbols of prosperity..."

“The world is always full of the sound of waves.The little fishes, abandoning themselves to the waves, dance and sing, and play, but who knows the heart of the sea, a hundred feet down? Who knows it depth?”