s far as works of art go, this one was technically crude: an unlawful doodle of a robot in blue ink, one metallic arm held up as if saying hello He resided on the side of a fire department call bor somewhere on the downtown end of Lexington Avenue-about a foot tall. with a hasty, crooked smile and a pair of sleepy eyes that suggested he might be stoned. For years I saw him almost daily as I made my way around the neighborhood. Il lived in the area then. And, everyday, without faiL he would dutifully greet me with a wave of his wrench-shaped hand. There were days I felt compelled to wave back. This funny little creature wasn't the most eye-popping piece of street art I'd ever seen. It was neither elaborate. nor drenched with layers of socio-political meaning. It was a simple gesture, by an anonymous artist. yet it had the power to draw my attention on a daily basis, to turn a slab o dull municipal furniture into a dynamic piece of sculpture. In recent years. as street art has gone mainstream-assiduously documented in all manner of media. showcased in galleries. and acquired by museums it can be easy to forget about the visceral reaction that comes from simply stumbling upon a piece of art on the street. Mummies and men made of