Sculpture is three-dimensional artwork created by shaping or combining hard materials—typically stone such as marble—or metal, glass, or wood. Softer ("plastic") materials can also be used, such as clay, textiles, plastics, polymers and softer metals. The term has been extended to works including sound, text and light. Materials may be worked by removal such as carving; or they may be assembled such as by welding, hardened such as by firing, or molded or cast. Surface decoration such as paint may be applied. Sculpture has been described as one of the plastic arts because it can involve the use of materials that can be moulded or modulated. Found objects may be presented as sculptures. Sculpture is an important form of public art. A collection of sculpture in a garden setting may be referred to as a sculpture garden.