At the 34th street station there is an art display that I came apon the night I took the subway home at 4 in the morning. I was waiting for the Astoria train to come along and I heard a breif orchestral sounding riff. I went off down the platform to investigate. The green rectangular structure attached to the pillars have motion censors. When you wave your bag, umbrella or hand in front of the censor a short musical sequence follows. It was a nice addition to the hot and stuffy silence of the early morning station.