Artifact 12, Late Screen Age: the Threshold Wheel. Recovered intact from the mouth of a great glass hall, this rotating barrier of four transparent panels turned upon a central axis, admitting supplicants one at a time into the buildings the Ancients held most sacred, those towers of stone and mirror where they gathered by the thousands each dawn.
We have determined that the Wheel served as a rite of purification. No pilgrim could enter the tower directly; each was required to step into a sealed chamber of glass, press forward, and revolve a quarter-turn through nothing, a small pointless orbit performed before being permitted to proceed. This we read as a threshold offering: the worshipper surrendered a fragment of forward motion to the building itself, a tithe of momentum paid at the door.
The wear is instructive. The push-bars are worn smoothest at the height of an adult hand, but scored also at the height of a small child, suggesting the young were made to turn the Wheel unaided, their first initiation into the discipline of the towers. We note further that the Wheel could hold only one true believer per chamber.
Those who crowded in behind, impatient, are recorded in fractured glass and jammed axles: the sacred machine punished haste, pressing the greedy between its panels until they learned to wait their turn.
Nearby stood always a second, humbler opening, a plain hinged slab, unadorned and easy. The Ancients almost never used it. They chose the harder rite, the spinning glass, the pause, the offered circle, even in the cold, even in the rain.
They were a people who could not bear to enter anywhere the simple way. Every doorway they built asked something of them first, and this, we believe, is why they walked so heavily through the world: they were forever paying, at every threshold, for the privilege of arriving.