 Complete the following phrase:  1958 marked an international breakthrough when Kühns work was included in the West German pavilion display at the Brussels World Fair, forging for it an artistically forged mesh element, inspired by an x-ray of a human chest. Even after the sudden appearance of the Berlin Wall in 1961, Kühn was seen as a member of the artistic establishment, winning commissions from state authorities and respected for his inventive artistry in his unusual artistic niche, on both sides of the so-called iron curtain, despite the increasing semblance of permanence in the 