Art traditions vary enormously amongst and within these diverse groups. Indigenous art with a focus on portability and the body is distinguished from European traditions and its focus on architecture. Indigenous visual art may be used in conjunction with other arts. Shamans' masks and rattles are used ceremoniously in dance, storytelling and music. Artworks preserved in museum collections date from the period after European contact and show evidence of the creative adoption and adaptation of European trade goods such as metal and glass beads. The distinct Métis cultures that have arisen from inter-cultural relationships with Europeans contribute culturally hybrid art forms. During the 19th and the first half of the 20th century the Canadian government pursued an active policy of forced and cultural assimilation toward indigenous peoples. The "Indian Act" banned manifestations of the Sun Dance, the Potlatch, and works of art depicting them.