The Synchronous Chronolith

The chamber is a massive brass drum that resonates with the rhythmic thrumming of a heartbeat. Gleaming silver gears mesh perfectly within the walls, while the floor consists of three concentric, rotating rings of polished obsidian and gold. At the center sits a pulsating core of pure white light, housed inside a glass sphere etched with celestial coordinates. Wisps of blue vapor rise from the floor seams, smelling of cold metal and ionized air. Each ring features a different etched symbol that glows faintly when it passes under the shadow of a hanging bronze pendulum.