Perimeter Lock

A spent brass key lay discarded near the rear table leg. I placed my right heel plate against its notched edge, exerting measured forward thrust. The metal dragged across the floorboard seam with a sharp rasp, pivoting precisely ninety degrees. I then nudged a stray glass marble into the recessed groove between the key stem and the base of the leg. The spherical mass seated firmly, locking the assembly in place. A fortified sentry node now secures this dark junction.