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A black-and-white mosaic sphere—a work by Zurich-based artist Vreni Spieser (b. 1963)—hovers just above the steps of the entrance to the Raiffeisen branch in Zurich Wollishofen. Weighing 900 kg and measuring 110 cm in diameter, the hollow concrete ball is held in place by a steel mandrel. Positioned at the most prominent point on the main intersection of the city district, the artwork marks the corner building of a brick block development typical of the era of the city's expansion. Illuminated by the sun from morning to evening, the sphere seems to shine like a celestial body at the focal point of its orbit, and incorporates on its surface ornamental and decorative elements from decades past found on the neighbouring buildings. The zigzag pattern of a wrought iron gate, painted leaves from a doorway, the abstract features of a balcony frieze, stars from a relief, or the concentric steps of an oriel base are spread evenly across the surface.  At points, the border between the white daytime and the black night-time sides of the sphere cuts across the motifs, inverting their contrast. The black-and-white design emphasises the graphic qualities of the design, such as the fineness of the lines and the density of the colour fillings. 

To create the mosaic, the artist pieced together small 1 cm cubes made of white Carrara marble and black “Nero Assoluto” granite. Under the supervision of a terrazzo specialist, the joints were grouted, then the entire object polished and finally oiled, creating a closed surface that is completely smooth to the touch. 

The artist originally conceived the work for the bank's former location on the opposite side of the street. Since the structural integration was minimal and the original design for  for the same outdoor space, the artwork could be relocated without losing any of its impact. 


Work type
Public Art
Object dimensions
110 cm
900 kg

l'acier, béton



Raiffeisen Wollishofen branch, NL Zurich
Mutschellenstrasse 197
8038 Zürich


Details Name Portrait
Vreni Spieser