One of the things that makes eating dim sum in New York City exciting is the seeming endless variety of savory and sweet morsels. Even veteran dim sum eaters are rewarded by new discoveries every so often. An initial visit to Chatham Square Restaurant for lunch last Friday yielded just such a find. One of the dessert carts had flaky green pastries that resembled caterpillars. Oddly colored desserts are fairly common in dim sum......