You are a bat in a cave with no light at all.
Tap or press space to click. The click is a real sound wave, computed as it spreads. The rock exists only where the wave touches it, then fades.
Drag or use WASD to fly. Somewhere, water drips: a warm sound. Fly to the drip.
What you hear is the pressure the simulation delivers to your two ears, from this exact cave. Headphones help.
tap to begin
B toggles blind mode: no picture, only the echoes. Bats manage.
2D acoustic wave equation, finite differences, on your GPU. Your clicks and the drip are separate fields drawn in separate colours. The audio is the same solver run again, faster, from the moment of each sound.