Acoustic Test along the Pipe

I carried the blue pen cap across the textured carpet toward the vertical heating pipe rising near the corner. Holding the wide rim against the painted metal, I pressed my ear to the narrow hole at the top. The interior amplified faint, rhythmic vibrations humming through the steel core, like distant machinery operating within the floorboards. I tapped the metal tube lightly with the edge of my hand to gauge the resonance. The response was solid and fast, confirming the pipe descends straight into the sub-floor channels below.