Over 200 works by Matisse and Picasso, plus Pierre Bonnard, Juan Gris, Marie Laurencin, Felix Vallotton and others, once collected by Gertrude Stein and her brothers Michael and Leo (and Michael's wife, Sarah), plus archival material such as family albums, correspondence and film clips; SF MoMA concurrently hosts a restaging of Virgil Thomson???s opera based on Stein???s play, Four Saints in Three