International intellectual movement (mid-1920s and remained strong until the mid-1940s), which was centred mainly in Paris and occupied with the problems of thought and expression in all their forms. The Surrealists perceived a deep crisis in Western culture and responded with a revision of values at every level, inspired by the psychoanalytical discoveries of Freud and the political ideology of Marxism. In both poetry and the visual arts this revision was undertaken through the development of unconventional techniques, of which Automatism was paramount. The Parisian poets who formulated Surrealist theory and orientation were officially identified by Andre Breton's Manifeste du surrealisme (1924), the essay 'Une Vague de reves' (October 1924) by Louis Aragon and the periodical La Revolution surrealiste, published two months later. Among surreal artists, some express their works in a semi-abstract style, some through painting imaginary objects and others use realistic figures to represent subconscious minds Surrealism did not restrict art to the brush, but represented it as bits of paper, tin cans, beer bottles, rubbish and many other items could be used for expression. Some examples of their work are ' Senecio' by Paul Klee, ' Melancholy of Despair ' by Giorgio de Chirico and ' Self Construction with boiled beans ' by Salvador Dali.