Photograph: Christian Hartman

Q I’ve noticed a few pieces of sidewalk slabs around SoHo that have some Keith-Haringesque art. The one on the corner of Broadway and Prince Street seems to be signed by “Ken ’84.” I love them and worry they’ll be destroyed/removed one day, and wonder, Who is Ken? What happened in 1984?—Michele Perez, East Village

A The man behind the masterpieces is Kenichi Hiratsuka, a native of Japan who moved to NYC in 1982. In those days, the Cold War was on everyone’s mind and Hiratsuka wondered, “What would be left over in human society, just in case humans go extinct?” So he started carving into the city’s sidewalks. Since the artist planned on his work surviving atomic warfare, you can probably quit worrying about the artsy walkways being demolished.

Hiratsuka’s newest sidewalk carving was just completed in February 2008; check it out at 25 Bond Street between Lafayette Street and Bowery. It’s based on the same concept as his earlier works: “If I start carving one continuous line, a spiral, that never crosses itself…just expanding, expanding, expanding, expanding, then I can carve all the earth into a sculpture,” he says.