The "Raumknoten" and "Raumschichtungen", filigree and multilayered sculptures that have been created since the mid-1950s and define space, form the first autonomous focus in the work of Otto Herbert Hajek. Here, sculpture is connected to space as a core volume; subsequently, the sculptures develop into rhythmic accents in space. The sculpture, preformed in wax, forces in its free, lively, multifaceted growth in bronze casting to the unique.
Since the 1960s, Hajek's structured surface of bronze is replaced by the use of other materials, such as wood or steel, and by more rigorous and smooth forms. In the "color paths" of the 1960s, the coloristic design principle increasingly prevails in the integration of the sculpture into its surrounding space. The eye is guided by color accents, especially in the form of color paths. Initially, the surface still remains structured by the material used; later, color and smooth forms apply more and more signal-like effect through geometric elements.