The distinguishing feature of the Kö-Bogen is its striking façade of glass and white natural stone, broken by diagonal cuts on the north and west sides. Strähle also incorporated this curved form in the interior when partitioning the office zones using its fully-glazed System 2300. Ceiling-high solid doors show the way optically while open and closed areas provide the space for communication and rest zones typically required in offices. The structural glazing variants in mullion construction provide for transparency as well as for interiors flooded with light thanks to a flush-fit all-glass look.