Günther Uecker's gigantic apparatuses make us think of archaic activities, such as ploughing and harrowing a field. Even more, however, they remind us of the monotone repetition of a mantra, a meditative movement circling around itself. In the late 1960s, Uecker abandoned the rigorous formal language of ZERO and turned towards new content. He began to work with materials from nature, and in 1965 created his first 'Sandmill': two rods circling around a central axis. Attached to these rods are cords with knotted ends, which continuously plough through the sand. Without interruption, in constant rotation, traces are engraved in the sand and then erased again. As an observer, we can never conclude the observation of this unending movement and transformation, but can only break it off. The formation of the sand undergoes constant change, and this is precisely what interests Uecker: the demonstration of time and the changes in something which remains the same forever.