points out a video demonstration of a 3D input system
which senses the user's hand position, but without requiring the user to touch a controller or wear a trackable position indicator. From the provided description: "Utilizing the theory of electrostatics, we have designed a low-cost human-computer interface device that has the ability to track the position of a user's hand in three dimensions. Physical contact is not required and the user does not need to hold a controller or attach markers to their body. To control the device, the user simply waves their hand above it in the air."