Sculpture is a three-dimensional work of art that artists traditionally create by carving, modeling, or casting a variety of materials that include wood, marble, clay, or bronze. In the modern and contemporary traditions, the sculptor may combine separate materials and found objects to construct an assemblage. Sculpture may stand free on a base or directly on the ground; it may also be attached to a wall or hang from a ceiling. Materials accepted as appropriate with which to make sculpture have been expanded to include everyday objects, textiles, industrial metals, and even the earth itself. The modern and contemporary sculptor feels that any physical materials are acceptable if they provide a satisfying means of personal expression.