Max Bill, is considered the father of concrete art in Europe, founder in 1944 of Konkrete Kunst, a movement of artists, graphic designers and architects gathered for the purpose of creating non-figurative works based on very simple formal elements: orthogonal lines and primary colors without shades . Inspired by the art of Kandinsky and Mondrian and influenced by modern scientific thought, Bill develops his own objective creative method, where line and color are subject to the rigid application of mathematical formulas. In fact, starting from the mid-thirties, mathematics became the primary source of inspiration for Bill. Schwarzes viertel, fourth black, is an emblematic example. The work on display, dated 1959, has a lozenge shape, it is a white square rotated by 45 degrees inside which there is a longitudinal black section that corresponds to a quarter of the surface. The titanium white color - spread with a spatula and replaced by the cream white used since the 1930s - plays a fundamental role in Bill's works: moving away from the theories of Kandinsky and Malevic, white is in fact considered by the Swiss artist as a all effects.