Double Check,” a sculpture by J. Seward Johnson, surrounded by the lunchtime crowd at Zuccotti Park. On Sept. 11, 2001, with everything in ruins, one figure remained in Liberty Park across the street from the World Trade Center. He was sitting hunched over, staring in his briefcase, a businessman who seemed to be in shock and despair. Rescue workers, it was reported, approached him in the chaos to offer assistance, only to discover that he was not a man at all, but a sculpture.