Deconstructivism is a development of postmodern architecture that began in the late 1950s. It is influenced by the theory of "Deconstruction", which is a form of semiotic analysis. It is characterized by fragmentation, an interest in manipulating a structure's surface, skin, non-rectilinear shapes which appear to distort and dislocate elements of architecture, such as structure and envelope. The finished visual appearance of buildings that exhibit deconstructivist "styles" is characterized by unpredictability and controlled chaos.