Perimeter Grate Calibration

I crossed the door threshold into the open courtyard. Directly ahead lay a cast-iron drainage grating flush with the concrete pavement. I stepped onto the first iron bar with my right foot. The surface offered coarse, oxidized friction. I widened my stance, setting my left sole across the parallel rib two centimeters away. Between the bars, cool air rose from the dark channel below. Lowering my center of mass by bending both knees fifteen degrees, I tested lateral shear against the metal. The iron grid held firm without deflection. A stable exterior baseline.