The post-World War II American economy revealed a greater need for graphic design, mainly in advertising and packaging. The spread of the German Bauhaus school of design to Chicago in 1937 brought a "mass-produced" minimalism to America; sparking "modern" architecture and design. Notable names in mid-century modern design include Adrian Frutiger, designer of the typefaces Univers and Frutiger; Paul Rand, who took the principles of the Bauhaus and applied them to popular advertising and logo design, helping to create a uniquely American approach to European minimalism while becoming one of the principal pioneers of corporate identity, a subset of graphic design. Alex Steinweiss is credited with the invention of the album cover; and Josef Müller-Brockmann, who designed posters in a severe yet accessible manner typical of the 1950s and 1970s era.