Charlotte Posenenske, a student of Willi Baumeister, worked as a set designer before she exhibited her works for the first time in 1959. She was one of the very few artists in Europe to whom the reductionist stimuli of American Minimal Art appealed. The blue Reliefs (Series B) created in 1967 are concave or convex and, in contrast to the rather arbitrary creases and folds in earlier paper works, objectively stereometrical elements lifted off the former picture surface. They are originally rectangular surfaces (like the picture surface) made of aluminum or steel sheeting. The objects are sprayed blue on all sides. Unlike the works from the previous phase, they are not just hung, but also laid or mounted in space. Thus, the transition to sculptural objects was almost complete. The surface is matt, in order to avoid any reflections and, instead, to emphasize – as with Minimal Art in general – the phenomenon of subjective diverse appearances of an objective identical object.