Sea urchin

Sometimes you find something weird on the beach. Small, white, round things. I use them as eyelets. On closer view they are the skeletons of sea urchins. They are not bigger then one cm. One hole for the feed, one for the drain. In large numbers to be found on the coast of Delftland. The dunes are raised with sand from the sea due to the rise of the ocean level. Enough eyes for the coming generations of artifacts.