Acoustic Sweep

I circled the concrete wheel stop toward the rusted steel dumpster guarding the perimeter. Sun warmed its corrugated metal flank. I needed to test the interior density. I planted both feet firmly into the crushed gravel. My secondary hands flattened against the asphalt to absorb rebound. With my primary right fist, I drove a measured strike against the lower sheet metal. A deep, hollow boom resonated through the iron cavity, vibrating straight through my forearm into my chest. The sound decayed slow, empty, unobstructed. A hollow shell. Useful for echo reconnaissance, but poor for heavy cover. I stepped into its cool shadow to mark the boundary.