Tribal dragon and yin yang design

It lifts its head clear of the swell, and you see the spines along its neck, sharp as the tines of a comb. Its mane streams back in pointed black blades, and behind it the water coils out in long tapering strokes that thin to nothing, so the foam looks like ink poured onto a chart. Carrow used to say the beast was guarding something beneath the rock. You never believed him until the night it circled the lighthouse twice, slow as a clock hand, while the tide turned under it in a great split circle, one half white, one half dark.

You fill the reservoir, trim the wick, and strike the match with fingers that will not quite keep still. The beam swings out across the water and falls full on the creature's eye. For a long moment it hangs there, neither coming nor going, and you understand that the light is not chasing it away. The light is only showing it the way back out to the deep water, where the dark half of the circle is waiting for it.

By dawn the sea is flat and empty. On the lamp-room glass lies a single curl of black weed, shaped like the tail of something that has decided to go home. You wind the clockwork, sweep the steps, and write in the log: wind west, lamp lit, company departed at four.