Read the following passage by Sana Malik, describing a visit to an automated lighthouse.

When I first saw the lighthouse, it was not shining. It stood above the harbour, unlit, a white thumb pressed against the grey sky. From the deck of the supply boat, I watched it rise and fall behind the waves. Each time it reappeared, its stillness seemed deliberate, as if it had chosen not to notice the water throwing itself against the rocks below.

Inside, everything had a place. Spare bulbs rested in padded boxes; tools hung in dark outlines painted on the wall; tins of oil stood in a row with their labels facing forwards. Even our wet coats were immediately captured by two hooks beside the door. After the disorder of the crossing, the neatness was comforting. The lighthouse appeared to have prepared for every possible need before we arrived.

We began to climb. The iron staircase curled upwards through the tower, tightening around us with each turn. At first, I could hear the technician explaining the machinery above. Then his words became fragments dropped through the stairwell: "motor", "battery", "automatic". Soon I could hear only our feet and the small complaint of the metal beneath them.

The lantern room was brighter than I expected. Its glass walls gathered the pale afternoon and arranged the harbour below us like a map. Boats moved along calm lines of wake. Roofs fitted together in tidy blocks. The road out of the village was a narrow thread laid across the hills. From that height, the coast seemed fixed and readable, held in place by the patient machinery at the centre of the room.

Then the fog arrived.

It did not roll towards us like a wave. One moment the far headland was visible; the next, it had been rubbed out. The harbour disappeared section by section: first the road, then the roofs, then the water itself. Within minutes, the glass walls showed nothing but a shifting whiteness. We had climbed above the sea only to lose the world.

The lamp switched on. Its beam passed through the room at steady intervals, briefly whitening our faces before turning away. Outside, the light formed a bright door that opened onto nothing. I knew that ships beyond the fog might depend on that repeated signal, yet from inside the lantern room it seemed strangely uncertain, forever searching the same blank space and finding no reply.

A horn sounded beneath us. The noise entered my ribs before I understood what it was. The tower trembled, and the glass gave a faint answering rattle. The technician continued checking the controls, apparently satisfied, while I gripped the rail and waited for the sound to come again.

On the way down, the staircase no longer seemed like part of a carefully organised machine. It was a thin coil suspended inside a hollow tower. Yet when we stepped outside, the beam was turning above us, calm and regular. I understood then that the lighthouse did not hold the coast in place. It searched for the coast again and again, refusing to stop simply because it could not see it.