Acoustic Signal Test

Night had settled, and I navigated back inside to assess the perimeter along the baseboards. Beside the wall, a hollow steel marble rested against the base of an upright copper heating pipe. The acoustic density of the metal conduit suggested a viable communication channel. Planting my feet firmly on the oak floorboards, I leaned forward and struck the copper pipe with the steel sphere using calibrated momentum. A clear, resonant chime vibrated through the metal cylinder, reverberating upward into the quiet rafters before slowly decaying. Structural resonance confirmed. The interior remains sound.