The competition brief for the Kant Dreieck in Berlin called for a slender tower that would create a landmark profile on the city skyline. Josef Paul Kleihues won First Prize, and the building was completed in and awarded the 1994 Prize from the German Association of Architects.

The 6,050 square meter building houses offices and commercial space. The 11 storey (56 meter tall) tower is designed on a square module with a steel cube on top of a stone cube, placed alongside a five story triangular glass structure that relates in scale to the neighboring buildings.

A strong contrast between the two cubes is provided by the white metal cladding, with exposed cross bracing, and the gray stone cube of gneiss, a crystalline type of slate; the square window pattern unifies the cubes. The lower section, triangular in plan, has a curved facade on its long side generated by the line of the adjacent "S" Bahn rail line. Access to both buildings is provided through the main entrance in the Tower Block. There is a lobby on each floor with access to the offices and a smaller lobby that provides access to the open plan offices in the triangular glass building.

The "shark fin" shape of the enormous aluminum weather vane, which sits on top of the tower and turns in the wind like a giant sail, follows the ground plan configuration of the building section, which in turn refers to the shape of the site. The building's "cocks comb", so called by Kleihues, provides an identity and contributes to the identification of the building as a new landmark. The building is located near three buildings designed by Bernhard Sehring around the turn of the century: the Theater des Westerns, the Fasanenstrasse Artist Building, and the Delphi Palais de Danse (now a movie theater). The small square is planned to relate to the forecourt of Theater des Westerns.

"The tower building clearly gives away that it found its form in the rational tradition by stacking two cubes (stone and steel) in a static gesture, but this is countered by the crowning sail turning in the wind, which can be understood at first as a playful element with no specific purpose at all in brief, an ornament. But the sail makes it quite clear that the two principles, rationality and poetry, permeate each other. Its shape is derived from the shape of the site, transposed into the vertical; the site is shaped like this as a result of a significant urban intervention in the district in the 19th century a curved railway line. Beyond this, the sail refers ironically to Modernism's criticism of ornaments. The north side of the facade (Fasanenstrasse) follows a right angle pattern derived from the architectural grid. The influence of the underlying design process expresses itself in the articulation of all elements on a basic 15 centimeter module. This system of dimensions, abstract in principle, means that the building appears as a complete aesthetic unit in the sense of architectural autonomy. But the curved rear of the building is based on a geometrical system determined by correspondence with the curve in the railway line. In contrast to the architectural theme of the building grid, it is based on an urban fact and relates irregularly to the architectural grid. Both systems, urban context and architectural autonomy, contradict each other at first, which is clear in the detailing inside the building and also on the rear side."

Excerpt from an essay by Winfried NerdingerJosef Paul Kleihues "Themes and Projects"Birkhauser Verlag