The absence of physical substance, commonly referred to as 'emptiness,' becomes a canvas for sound... Examining the oscillations that dance in these barren spaces helps us understand their silent symphony.

Echoes, as defined by reverse propagation of sound waves, reveal insights into spatial geometry. Each reflection offers data: time, angle, and intensity intertwined in a complex matrix.

The art of listening in these spaces is akin to drawing a shadow with sound, mapping the unseen through a sequence of auditory memories. What stories do these echoes relay, and what truths dare they unfold?