The Black Square

Black Square against white background became the symbol, the basic element in the system of the art of suprematism, the step into the new art. The artist himself created several variants of the Black Square. All four Squares painted by Malevich from 1915 to the early 1930s developed the same idea. Different are not only the sequence and year of creation, but also the color, design and texture. Malevich turned back to the Black Square every time he needed to present his work in an assertive and significant way, often in connection with the most important exhibitions. However he always created a new version rather than copied the previous one.
—http://www.russianpaintings.net/doc.vphp?id=126