When a work of art is displaced from one institution, it does not always disappear — sometimes it finds a new home through the very hands that once helped steward the place it left. David Rubenstein, who recently departed as chairman of the Kennedy Center, has purchased the blue sculpture removed from that institution and arranged for it to be displayed at the National Gallery of Art in Washington. The act quietly reframes what might have seemed like a loss: a cultural object, caught in the currents of institutional change, is carried forward rather than set aside.