THE artist Christo (sculptor? happenings director? temporary environments creator?) has proposed for New York's Central Park what is undoubtedly his largest project to date: “The Gates,” which is to be the embellishment of 27 miles of walkway with simple rectangular archways from which fabric curtains will hang. Christo, as is well known, is not content to confine his art to studios, or indeed to any indoor space, nor does he create permanent, free-standing objects for the outdoors. He first became known for wrapping very large objects so that they looked like packages. Thus, he wrapped the Kunsthalle in Bern, Switzerland (1968) in 27,000 square feet of reinforced polyethylene and nylon rope (when a package rises to a giant scale, the packaging materials must be adapted accordingly).  He went on to wrap-though the term “wrap” hardly seems appropriate to the ungainly result-a section of cliffs on the coast of Australia in a million square feet of material (1969). An enormous curtain was then hung across a valley in Colorado (200,000 square feet of nylon polyamide, 110,000 pounds of steel cable, 800 tons of concrete) in the early 1970’s. And, in perhaps his biggest project to date, a running fence of fabric 24 miles long and 18 feet high was strung across the peninsula of Marin Country, California (1972-76).  In the project that most closely resembles the one proposed for Central Park-though on a much more modest scale-a few miles of walkways in Loose Park, Kansas City, were carpeted loosely with 15,000 square feet of fabric.