Echolocation
Navigate a dark room using sound alone. Click anywhere to emit a pulse — circular wavefronts expand outward, bouncing off walls and objects. The scene reveals itself only through echoes.
How it works
Echolocation is a biological sonar used by bats, dolphins, and some cave-dwelling birds to navigate and hunt in environments where vision is limited or useless. The animal emits a short burst of sound — a click or chirp — and listens for the returning echoes. By measuring the time delay between emission and return, the brain calculates the distance to each reflecting surface: distance equals the speed of sound times the round-trip time, divided by two.
But echolocation provides far more than range. The frequency shift in returning echoes (Doppler effect) reveals whether objects are approaching or receding and how fast. The difference in arrival time between the two ears gives angular position. The spectral content of the echo — which frequencies are absorbed or enhanced upon reflection — encodes information about the object's size, shape, and even texture. A bat can distinguish a moth from a leaf in total darkness, using acoustic information alone.
In this simulation, you experience a simplified version of this process. The room starts completely dark. When you click, a circular wavefront expands at the speed of sound, and objects are revealed only at the moment the wavefront reaches them — then they fade back into darkness. Through repeated pulses from different positions, you build up a spatial map of the room, just as a bat would. The key insight: spatial awareness does not require light. It requires information, and sound carries plenty.
The objects in the room can be dragged to new positions, letting you experiment with how object placement affects the echoes you receive. Try placing objects close together and far apart, and notice how multiple pulses from different angles help you resolve ambiguous arrangements.