The Barnes Foundation (opened in 1925) is as famous for its idiosyncratic, symmetrical "ensembles," wall compositions organized according to the formal principles of light, line, color, and space, rather than by chronology, nationality, style, or genre. In the ensembles, Albert C. Barnes (1872-1951) combined African sculpture; antiquities; Asian art; Native American ceramics, jewelry, and textiles; manuscripts; and old master paintings, as well as...