The black square by Kazimir Malevich stands paradigmatically for Russian Suprematism and thus for the concept of art as a force for political change. On the occasion of the exhibition “Kazimir Malevich and His Students: 100 Years After the Black Square” at the National Museum of Thessaloniki, the artist implemented an action in the Greek city, one that was previously realized in Hamburg in 2007. At a time when the economic and political situation of Greece could not be more volatile, he rendered Malevich’s icon in public space. As a moving mass of people clothed in black or white the black square on a white ground becomes a mobile agora and trigger for public debate. Whereas the version in oil on canvas from 1915 in the museum is a historic symbolic vehicle, the group of people develop their political potential in this collective and public action. (JO)