These include pieces by important 20th-century masters: Gaston Lachaise, Constantin Brancusi, Jacques Lipchitz, Barbara Hepworth, Isamu Noguchi, Claes Oldenburg, GeorgeRickey, Richard Serra, David Smith, Mark di Suvero.
In the 1980s, through the late Barbara Grigor, a champion of many a Scottish artist, Wyllie met the American kinetic artist, GeorgeRickey, who invited him to work with him in America.