Patterns of use, or nonuse, are beginning to clarify the nature of the Brooklyn garden. I was reminded of that yesterday when we made our first visit to the Barnes Foundation in Philadelphia, the new building on Benjamin Franklin Parkway where Albert Barnes’ extraordinary art collection is now on display. In the lower lobby, and extending up through two levels to the roof opening, is a striking glass-enclosed garden planted with ferns and several tall Ginkgos and Sweet Gums rising through the building. Most definitely a garden to be looked at. There’s no way to enter it.