It can be made from many materials, including metal, plastic, and wood. People have been using natural objects, such as tree stumps, rocks and moss, as furniture since the beginning of human civilisation. The use of scarf joints to join two shorter pieces together and form a longer beam was one example of this, as well as construction of veneers in which low quality cheap wood was used as the main building material, with a thin layer of expensive wood on the surface. Mattresses, rugs, and blankets may have been used, but there is no evidence for sheets. The most commonly used metal was bronze, of which numerous examples have survived, for example, headrests for couches and metal stools. In this era, most of the furniture had metal and enamelled decorations in it and some of the furniture was covered in inlays of marbles lapis lazuli, and porphyry and other stones. Furniture can be made using a variety of woodworking joints which often reflect the local culture. The nineteenth century is usually defined by revival styles. The practice of using natural objects as rudimentary pieces of furniture likely dates to the beginning of human civilisation. Chests were used for storage of clothes and personal items, and were usually rectangular with hinged lids. Some imported wood such as satinwood was used for decoration. Both hardwoods and softwoods are used in furniture manufacturing, and each has their own specific uses. Highest quality wood will have been air dried to rid it of its moisture.