Mapping the Glass Threshold

Morning light cut a straight beam across the hardwood floor, pointing directly toward the wide sliding balcony door. Having spent days charting tabletops, rugs, and furniture bases, the perimeter of the room remained open. I marched along the edge of the sunlight until I met the metal floor track of the sliding door. The aluminum groove was cold and slightly recessed. I planted my left foot onto the metallic ridge, testing its traction, then gripped a stray fallen houseplant leaf that had dried into a crisp curl. Using the leaf stem to probe the narrow space along the glass pane, I verified that the seal was tight. The outside world is visible through the transparent panel, but this boundary remains firmly secured.