Devil's Tuning Fork

Origin
Devil's Tuning Fork is a first-person exploration/puzzle game in which the player must navigate an unknown world using visual sound waves. Inspired by M.C. Escher’s classic optical illusion and the echolocation of dolphins, The Devil’s Tuning Fork allows the player to explore a new mode of perception through sound visualization. As a mysterious epidemic causes children everywhere to fall into comas, one child wakes up in an alternate reality. It is up to this child, the player, to determine the cause of the epidemic and save the other children trapped here. By way of the devil's tuning fork, a magical instrument that allows the player to perceive sound waves, the player must find all the children and successfully escape this alternate reality, thereby waking up from the coma.

Effects
The Devil's Tuning Fork allows the user to use echolocation, producing high, low, and concentrated bursts of sound, the first can allow "sight" of farth distances, the second can detect flawed objects and surfaces, and the latter can be reflected off of mirrors. However, it also induces comas in nearby children.