In Apr. 1995, at street of AOYAMA in Tokyo, I have installed my pieces in public space at several ad signboards which had been mounted on various trees along a particular street. Of course I had gotten no permission to install them. Perhaps the ad boards might be also gotten no official approval as well. The pieces consist of a small loudspeaker, a small dry battery and thin wires. The electric cables were directly attached by soldering to the ropes of sign boards in order to make up electrical contact points, so it was seemingly suspicious objects. I was thinking the ad boards have caught various physical vibrations, from winds, traffic and other aspects of street events. So, I made up the electrical contact points. My pieces had been making out small noise sounds were generated by the electricity intermittently occurring at the contact points. This work was done under the strictest security conditions in Tokyo due to the cult's serious terrorist attack of a massacre. Interestingly, the piece was still in place a few months later.