Abstract art (abstract art image ) is not realistic, an image is often based on an actual subject, place, or feeling, but the form of representation differs from the idea. Pure abstraction art can be interpreted as any art in which the depiction of real objects has been entirely discarded and whose aesthetic content is expressed in a formal pattern or structure of shapes, lines and colours. This is often a common theme in African art. Non-representational lines, colours, shapes, and forms replace accurate visual depiction of objects, landscape ( landscape image ), and figures. The subjects often stylized, blurred, repeated or broken down into basic forms so that they become unrecognizable. Intangible subjects such as thoughts, emotions, and time are also expressed in the abstract art form. This general term refers to works executed in accordance with the principle that lines, forms and colours possess aesthetic values which may be arranged into pleasing compositions devoid of normal subject matter. In the late 19th century the traditional European conception of art as the imitation of nature was abandoned in favour of the imagination and the unconscious. Abstraction developed in the early 20th century with such movements as Fauvism, Abstract expressionism art, Cubism, and Futurism. Vasily Kandinsky is credited as the first modern artist to paint purely abstract pictures. Piet Mondrian's De Stijl group in The Netherlands widened the spectrum. Abstraction continued to flourish between the two world wars, and after the 1930s it was the most characteristic feature of Western art.