An interactive media table that includes a tabletop that supports of
plurality of movable objects each of which is identified by a unique
identification code and each of which can be moved from place to place on
said tabletop surface by one or more media table users. A display unit
produces a visual image on the surface of the tabletop surface and a
position tracking system determines the current positions of each of said
movable objects by transmitting timed acoustic signals to each movable
object, sensing the timing of arrival of these signals using an acoustic
pickup on each object, and estimating the location of the object by
triangulation. An infrared communications network exchanges timing
information, commands and data between the objects and a controller which
provides an API to a personal computer which executes an application
program that controls the display.