Behind her, the dancing Cherokee boy that Betty Foy Sanders painted about 40 years ago appeared to be in constant motion, as was she, during Saturday's unveiling. Sanders, 87, sat in a wheelchair but explained that this was her first time using it, at a doctor's insistence, for a public ceremony that might have kept her on her feet. In front of faculty of the Betty Foy Sanders Department of Art, surrounded by the collection that also bears her name, she used a strong voice and active hands to talk about her continuing contributions, direct and indirect, to art at Georgia Southern University.