The parameters can be saved for later recreation of the performance in a "library of possible outcomes," Bukvic says. "It's like virtual Play-Doh, where each [finger] inflection affects the actual output -- aural, visual, etc. The composition and the performance become one."

Microsoft is working with several commercial partners, including Starwood Hotels & Resorts Worldwide, to introduce Surface, which is due to ship in the spring. It will initially target leisure, entertainment and retail applications, says Mark Bolger, director of marketing for Surface Computing. For example, he says, one could imagine a hotel guest using a "virtual concierge" in a Surface computer in the lobby to manipulate maps, photos, restaurant menus and theater information.

Bolger says Surface has four defining characteristics, traits likely to be seen in many future touch-based devices: direct interaction (no keyboard or mouse), multitouch interface, multiuser input and object recognition -- for example, a waiter places a bottle of wine on Surface and it brings up pictures of the winery.

Just what is meant by "multiuser" is a matter of some disagreement. Adam Bogue, vice president of business development at MERL, says MERL's DiamondTouch Table is the only truly multiuser touch device available because it is the only one that can identify different users who are touching it simultaneously. "Our whole approach has been to support small group collaboration," he says.

With DiamondTouch, users literally become part of the system. Multiple antennas embedded under the surface transmit small radio-frequency signals to users' fingertips. Explains Bogue, "When you touch the table, you are capacitively coupling yourself to the signals, completing a circuit through you and into your chair. Each chair is wired into a separate receiver channel."

MERL made its first DiamondTouch device in 2001 and has since sold more than 100 of them to university labs and to a few companies looking to incorporate the device into their own systems. The organization is now working on applications, the first ones in GIS and CAD, and it sells a kit of software and hardware that companies can use to develop their own applications.

At the end of January, Bogue says, MERL will announce that it is spinning off the DiamondTouch business to an independent company to be called Circle Twelve.

Of course, researchers and inventors have envisioned even larger touch displays, including whole interactive walls. A quick YouTube search for "multitouch wall" shows that a number of these fascinating devices have reached the prototype stage, entrancing multitudes at technology conferences and in other public spaces. You can even buy one such device -- the Interactive Media Wall developed by multitouch innovator Jeff Han and his company Perceptive Pixel Inc. -- for US$100,000 at Neiman Marcus.

But experts predict that this is just the beginning.