Medium refers to the materials used to create a work of art. Sculptors use materials like metal, wood, and stone. Painters use pigments on surfaces like canvas or paper. Musicians use instruments and the human voice. Architecture occupies space using materials like wood, bamboo, bricks, and concrete. Technique is the method artists use to manipulate materials to achieve their desired effect and communicate their concept or meaning. Contemporary artists expand the range of media and techniques, creating more process-based, site-specific, interactive, and collaborative works that push the boundaries of traditional art forms.