One New York City Parks Commissioner describes the artist Christo and his wife/collaborater Jeanne-Claude as “relentless, in the best New York City way,” and the massive draping of Central Park is the proof. The project, which will come to fruition this weekend, is the culmination of a quarter-century of begging, cajoling, and convincing by the artists, who use the proceeds from small, collector-friendly works to fund their huge flights of artistic fancy.