New Yorkers are hearing things these days — and it is coming from the bushes. It is the sound of concrete crickets, little devices created by artist Michael Dory that play bits of music and make cricket-like sounds. Dory hides small sound devices in containers around the city, similar to the way graffiti artists spray paint their art on walls without asking anyone's consent. The crickets are just loud enough for passersby to hear. And like their namesake, the crickets stop ch