Ultrasound to give feel to games describes a breakthrough by some Japanese researchers in the world of haptic technology, as they are able to convey a sense of touch via an ultrasound interface without using gloves or other mechanical devices. Word is: "The team's prototype system includes a camera which tracks the position of a user's hand and shifts the output from the transducers to move the focus around with the hand. The result is a feeling of tracing the edge or surface of the virtual object." Advantages of this approach include the ability to "touch" an object with both hands and the ability for multiple users to interface with virtual objects. Disadvantages include the limited amount of feedback they are currently able to generate and how their current prototype only works on a vertical plane. Thanks Mike Martinez.