The Threefold Sluice of Nhal-Tu

In the heart of the swamp stands a circular stone apparatus half sunk in black water, its surface carpeted with moss, orchids, and pale fungi that glow like dying embers. Brass rings as wide as cartwheels rise from the dais, connected by slim channels that still carry thin threads of water whenever the mechanism stirs. Carved frogs, herons, and serpents stare from the sides, each ring turning with a wet grind that sends ripples through the pool and makes the reed chimes whisper. When the device is close to correct, the water brightens with green light and the vines on the walls uncurl as if breathing; when it is wrong, the whole structure shudders and spits muddy spray.