The Human Piano. Not entirely a piano, but played through a human mixer nevertheless

Here's a video from Force Theory Productions, an arty outfit who have invented the Human Piano, seen in the clip. I couldn't quite work it out, so I asked them what's going on. Michael wrote back: "The idea is that sound through wire is low level electricty. That electricity can easily pass through human bodies. It works by taking a sounce [in this case several iPods] and having the outputs go into a large copper pipe. Whatever sound is being played out of the ipod is now in the pipes. Then someone grabs firmly onto the pipe (as how hard you grab will effect conductivity and therefore loudness). The sound is now in the person. On the other side of it, I have a tight copper pinky ring that has a wire attached to it. The wire goes to a mixer and to the speakers. Once I grab someones hand, the sound goes:
iPod → Copper Bar → Human → Me → Mixer → Speaker
"Polyphony is just touching more than one source imput at a time. The sound mixes inside me. The grand idea is to have a 16 person piano and play a piece just composed for the human piano in public at some point."