At first, I just gathered and used junk to make sound. Then I attached pickups, and finally set the junk objects up in a frame so that they were close enough for me to reach them. It was around the middle of the 1980s, I think. When I played with John Zorn in Tokyo (in '85), I was already using the instrument with a frame.
When I visited Leipzig to appear in a jazz festival in 1987, I made the instrument smaller, because I wanted to carry it in a travel bag. Then I realized it was better than before. So the smaller version became the prototype of the current version.
I pick up sound, attaching pickups to the instrument. I play it by bowing, hitting, rubbing and so on. It looks easy to play, but in fact it's pretty difficult. The smaller part is the first machine, and the bigger part with a bicycle wheel is the second one. The wheel doesn't turn.
The warty, automatically-moving balls are just toys that are sold at toy stores. I happened to find them at a toy shop when I played in David Moss's Japan tour (in 1990).
I'm not sure how many kinds of sound the instrument makes. I use digital reverb on the first part of the instrument. The reverb makes just seven or eight different sounds. There are also non-electric sounds. These vary. Different sounds come out depending on whether you hit or rub the instrument. But because they aren't digital sounds, the difference isn't clear. That's the weak point of the instrument. When you listen to it carefully, you realize that many kinds of sound come out of it.