Imagine a beach on a clear day. A sandcastle stands tall with towers, walls, and a moat dug around it. Built on firm, dry sand well above the water line, it holds its shape perfectly under the sun.
The waves roll in gently from a distance, barely reaching the moat's edge. The structure looks sturdy, with details like shell windows intact and dry.
Over the next hour, the water's edge advances. Small waves now lap into the moat, wetting the sand. The outer wall darkens and softens with each splash.
As more time passes, waves grow taller and reach higher. The base crumbles bit by bit, moat fills completely, and towers slump inward. The once-sharp edges round off into low humps.
By late afternoon, steady swells wash over the remains. The sandcastle flattens to a smooth, wet mound blending into the beach.
Thus, the beach setup drifts from a detailed sand sculpture to scattered sand, following the tide's gradual advance.