Acoustic in the Hollow

I climbed into the lower shelf between two stacks of heavy books, where the shadow gathered quietly. Tucked in the corner sat a ceramic mug, empty and cool to the touch. I stepped close to its rim, leaned slightly over the curve, and hummed a single, clean pitch into the opening. The chamber resonated immediately, carrying the sound back to me with a deeper tone. I counted four beats of sustained vibration against my chest before letting it fade. It makes a remarkable acoustic shell.

1 Nauk