This original version used ultrasonic frequency (i.e. sonar) to triangulate and detect user position in a small 3D area, a method comparable to the way ships use sonar to send a ping to the ocean floor and, thereby, calculate the ocean's depth by using the speed of sound divided by the time it takes for the ping to return to the ship. Experimentation with GASP by the Montréal-based performance ensemble PoMoCoMo resulted in the first major performance using this technology, Theory in Your Ear (1989), a work co-written by Bauer, Rafael Lozano-Hemmer, Andreas Kitzmann, Kim Sawchuck, Steve Gibson, Mark Bell and others, for Articule Gallery in Montréal. Worn by dancer Beth Kotecki, the tracker was a large, cumbersome plate mic that in its beta version only worked sporadically. A slightly more refined version of the system was produced and used for PoMoCoMo's Eastern Canadian/US tour in 1991-92 of ImMediaCy, a piece that premiered at the Music Gallery in Toronto and went on to Ars Electronica in Austria in 1992.

The shift from GASP to GAMS resulted in Objects of Ritual (Fig. 2), a work created by Bauer and Gibson for the Art and Virtual Environments program at the Banff Centre for the Arts (1993-94), and a slightly more reliable GAMS version premiered at

Figure 2. Will Bauer and Steve Gibson's Objects of Ritual

4Cyberconf at the Banff Centre. It was this version that in 1995 Bauer licensed to Martin Lighting of Denmark. Renamed the Martin Lighting Director (MLD), it offered a graphical software interface developed by Conroy Badger and Lozano-Hemmer. The software allowed for a graphical mapping of 3D space and presented space similar to the way Photoshop does, with different layers of media available to be assigned to lighting or MIDI data. The MLD was considerably more reliable than previous GAMS version and, while still difficult to setup, it was generally completely functional. Though while this version still functioned as a ultrasonic, non-networked system and collaboration between one user and the devices found in one space, it did offer 3D mapping, which allowed for full recognition of bodily movement by sensors in that space. (Fig. 3)

Figure 3. Graphical Mapping of 3D Space

Two of the first uses of this version of the tracking system were Idle Hands by Lozano-Hemmer and Gibson and The Trace by Lozano-Hemmer and Bauer. The latter went on to international recognition. Following their successful collaboration with the new system, Lozano-Hemmer went on to produce Displaced Emperors (1997) and Re-positioning Fear (1997), both part of the Relational Architecture series by Lozano-Hemmer (with Bauer). The latter piece received an Honorable Mention at Ars Electronica in 1998. Gibson went on to use the system in his solo piece, telebody, a co-production of The Banff Centre and karlstad University, Sweden, performed also at several venues in North America and Europe, including the Banff Centre, Open Space in Victoria, Canada, and Artnode in Stockholm. (Fig. 4)

Figure 4. Gibson's telebody

Early in the new millennium, Bauer broke with Martin and reverted the system back to its former name­­The Gesture and Media System (GAMS). At this time Acoustic Positioning Research (APR), the company Bauer founded, began working on an infrared version of the tracking system.

The infrared system differed from the ultrasonic version in that it used trackers with infrared emitters and four Firewire cameras with infrared filters. This design allowed the cameras to "see" the trackers since the filters removed all light sources from the camera views except for infrared sources, meaning that the system could work