From around the headland appeared two spherical vessels, carrying human figures, floating silently and slowly on the outward bound tidal channels towards the sea. Without propeller or oars, the urchins follow the whim of the estuarine flows, their speed dependant on the tidal forces. When the depths got deep enough, the urchins spun and flipped, performing tricks to delight the onlookers. They displayed themselves on the sand bank for all to see their delicate patterned structures. And back into the water they rolled, onwards, around the bend, disappearing as easily as they appeared, pulled by the calling of the expansive sea.