art also often make use of the environment. Ice sculpture is a form of ephemeral sculpture that uses ice as the raw material. It is popular in China, Japan, Canada, Sweden, and Russia. Ice sculptures feature decoratively in some cuisines, especially in Asia. Kinetic sculptures are sculptures that are designed to move, which include mobiles. Snow sculptures are usually carved out of a single block of snow about on each side and weighing about 20–30 tons. The snow is densely packed into a form after having been produced by artificial means or collected from the ground after a snowfall. Sound sculptures take the form of indoor sound installations, outdoor installations such as aeolian harps, automatons, or be more or less near conventional musical instruments. Sound sculpture is often site-specific. Art toys have become another format for contemporary artists since the late 1990s, such as those produced by Takashi Murakami and Kid Robot, designed by Michael Lau, or hand-made by Michael Leavitt (artist). Conservation Sculptures are sensitive to environmental conditions such as temperature, humidity and exposure to light and ultraviolet light. Acid rain can also cause damage to certain building materials and historical monuments. This results when sulfuric acid in the rain chemically reacts with the calcium compounds in the stones (limestone, sandstone, marble and granite) to create gypsum, which then flakes off. Severe air pollution also causes damage to historical monuments. At any time many contemporary sculptures have usually been on display in public places; theft was not a problem as pieces were instantly recognisable. In the early 21st century the value of metal rose to such an extent that theft of massive bronze sculpture for the value of the metal became a problem; sculpture worth millions being stolen and melted down for the relatively low value of the metal, a tiny fraction of the value of the artwork. Form Cultural Classical French Italian Renaissance Method Bronze Butter Electrotyping Gas Hill figure Living Mobiles Origami Plaster cast Tondo Tree shaping Wax Welded Application Architectural Garden Marriage stone Mask Monumental Relief Rock relief Sculpture garden See also List of sculptors List of female sculptors Outline of sculpture List of Stone Age art List of sculpture parks List of most expensive sculptures List of tallest statues Assemblage Cass Sculpture Foundation Notes References Boucher, Bruce, Italian Baroque Sculpture, 1998, Thames & Hudson (World of Art), Blunt Anthony, Artistic Theory in Italy, 1450–1660, OUP,