Natural and Invisible Human Interfaces   Huge advances in interface modalities are evident and imminent. This panel demonstrated and explored the most interesting, promising, and clever of these new developments, and their integration into exciting multimodel systems. Panelists took positions ranging from incremental to radical, and emphasized demonstrable and practical techniques.   Organizer Michael Harris Bear Systems, Inc.   Panelists Bill Buxton Alias|Wavefront   Caleb Chung Giving Toys, Inc.   Clark Dodsworth Osage Associates   Hiroshi Ishii Massachusetts Institute of Technology