I found these shells in Castle Glass, the City made of Sand. Its monumental walls were exquisite tributes to the sea. The roads: meticulously crafted, woven through sparkling dwellings, which were more like sculptures than homes. I could have stayed forever, but I had business to attend to, so I grabbed the shells and left. When I returned, the city was gone. The ocean had swallowed it. To my surprise, the shells in my pocket shook. Tiny creatures emerged. They crawled toward the beach and began shifting the sands, building something beautiful, as the tides receded to the ocean.