He never really meant it to be a functioning lighthouse. It started life with the battered remains of a ship – one of those iron steamships that had just become popular. Even metal had proved no match for the vicious rocks around the island. Balthazar reckoned, from the look of the thing, that a larger than average kraken had also had a go at it.

He could not live on land. He could not bear the way it stayed still, especially when he was trying to sleep. He never felt quite at home, or properly secure in an unshifting bed. And so he built a wooden crane, like he remembered seeing at docks around the world, and he used a salvaged boiler, several sturdy buckets and all the pipes he could beg, buy or steal, and he powered it with an engine. Swimming out to the wreck nearly killed him, but he managed to tow the back of the boat to shore. The front of the boat sheared off during this process and sank beneath the waves to join the multitude of wrecks on the seafloor.

He did the best he could with what he had. The result was round, and could never be steered, but it did float, in a low and wallowing fashion. It moved, and that was the main thing. As soon as it was sea-proof, Balthazar set up a hammock inside it, and felt a good deal better about life. His wife preferred to stay in the sea, and it meant he could be closer to her, which he preferred.

He called the round boat The Elegant Dolphin, in a fit of irony. Agile, The Dolphin was not, but sturdy she was. She survived that year’s winter storms, which were more violent than any he had ever known. So violent in fact that two giant cuttlefish washed up just round the coast. They were entwined, although whether they were fighting or had been trying to save and comfort each other, was anyone’s guess.

It was cold enough that they didn’t start rotting for quite some time. Being giant cuttlefish, they were not pleasing to eat, but they could be eaten, and they were right there, and sometimes he picked up fresh crabs who were scavenging from the carcasses.

When the spring came, it took them a while to rot. The crabs, and the crows did their best to speed the process. When the tide was high, the thing that inhabited the bay semi-emerged to feast. Eventually, only the bones remained.

Balthazar knew there would be enormous bones. He’d had months, waiting for them to emerge. Time to wonder, and dream, and plot. He had a fancy to build upwards. Why not? He liked lighthouses as an idea, had been glad of them many times when at sea. He knew the currents would wreck ships regardless of whether he put up a light. It was more a case of liking the look of them, and wanting something to occupy his life now that he could not travel.

It was only when he started turning giant cuttlefish bones into sections of wall that he also started wondering whether a light could have any other purpose, alongside signalling danger to those at sea.