The oldest known paintings are at the Grotte Chauvet in France, which some historians believe are about 32,000 years old. They are engraved and painted using red ochre and black pigment, and they show horses, rhinoceros, lions, buffalo, mammoth, abstract designs and what are possibly partial human figures. However, the earliest evidence of the act of painting has been discovered in two rock-shelters in Arnhem Land, in northern Australia. In the lowest layer of material at these sites, there are used pieces of ochre estimated to be 60,000 years old. Archaeologists have also found a fragment of rock painting preserved in a limestone rock-shelter in the Kimberley region of North-Western Australia, that is dated 40,000 years old. There are examples of cave paintings all over the world—in Italy, France, Spain, Portugal, China, Australia, Mexico, etc. In Western cultures, oil painting and watercolor painting have rich and complex traditions in style and subject matter. In the East, ink and color ink historically predominated the choice of media, with equally rich and complex traditions.
Painters work both indoors and out. Outside work is done in relatively mild weather. In some jobs, especially maintenance and redecoration of offices and buildings, the painter may be required to work evenings or weekends. Work is seasonal; however, new materials and methods tend to give more steady employment throughout the year. Physical and health hazards include the dangers of poisoning, falling from ladders and scaffolds, breathing paint fumes and dust. The work involves standing, bending, climbing and working with arms over the head much of the time.
Modern artists have extended the practice of painting considerably to include, as one example, collage, which began with Cubism and is not painting in the strict sense. Some modern painters incorporate different materials such as sand, cement, straw or wood for their texture. Examples of this are the works of Jean Dubuffet and Anselm Kiefer. There is a growing community of artists who use computers to "paint" color onto a digital "canvas" using programs such as Adobe Photoshop, Corel Painter, and many others. These images can be printed onto traditional canvas if required.
Component Interface: The component interface is an abstraction describing the behaviors of the components that you will eventually use in your program. Any objects that will use these components will do so through the interface, meaning that they are principally concerned with the abstraction (not the actual object). This is what allows both objects and wrapped objects to be considered to be the same type.