In the end, Wolf Prix and Helmut Swiczinsky had long ceased to be buddies in the traditional sense. Yet when Prix spoke by phone on Wednesday, his voice carried the weight of a dark black cloud, far removed from the sky blue that gave name to the architecture firm Coop Himmelb(l)au - a firm that could only have been founded in that singular year of 1968, and only in Vienna. It was established by two obviously crazy mavericks of architecture: Wolf Prix and Helmut Swiczinsky. On Tuesday, Swiczinsky passed away at the age of 81.

Prix shares this news, then hangs up, leaving behind the echo of "not yet" - referring to himself, that his own time has not yet come. Perhaps this great "not yet" would have pleased the philosophizing poet Swiczinsky. In life, there is death: not yet. And in death, there is life: no more. Life and death never truly meet - and this remains cheerful even when one must acknowledge that the world has definitively lost a great cloud-builder in Swiczinsky. Another one. There aren't many left.

For decades, anyone who called Coop Himmelb(l)au and was put on hold would hear "Gimme Shelter" by the Rolling Stones. Like the Stones, writes Wojciech Czaja in the Standard, one must imagine the buddies Prix and Swiczinsky: once inseparable, achieving greatness, lifting the world off the hinges of Biedermeier conservatism, building with fire and passion, and always good for a "manifesto." What they built was always baroque 'n' roll - precisely because they worked so intensively against their baroque hometown of Vienna with yearning futurism.

But eventually came the break. In 2006, Helmut Swiczinsky departed as a partner from the firm that had by then become internationally known rather than merely notorious, at a time when Coop Himmelb(l)au had become one of the biggest players in the international architecture business. The very word "player" would have tormented Helmut Swiczinsky. He was always the quieter partner. But Prix now says quietly: "He was a friend." Perhaps even: the friend.

Helmut Swiczinsky was born in 1944 in Poznan. He grew up in Vienna, studied at the Technical University, and subsequently at the Architectural Association in London. Swiczinsky was not yet 25 years old when he - traveling by plane from Spain back to Vienna together with Prix - decided to found an architecture group. Looking up at the sky, where ideas can often be grasped as if with hands, they found their name: Coop Himmelblau (Sky Blue Cooperative). The parenthetical "l" would come later, transforming the blue into "blue building."

"Sky blue is not a color," the Coop founders wrote, "but the idea of making architecture light and changeable like clouds through imagination." Admittedly, much later they would use quite a lot of steel and concrete on earth for this purpose. Yet their greatest and most inspiring buildings always challenge gravity - if not physical gravity, then at least mental gravity.

The names of early Swiczinsky-Prix projects say it all: "The Cloud" (before one could archive piles of data there for a fee to feed the foolish AI), "Heart Space Astro Balloon," "House with Flying Roof," "Flame Wings." Art for art's sake? No. This was art for architecture's sake. Few other '68ers succeeded in revitalizing the tired postwar modernist building culture with an overdose of political and social utopia that was simultaneously indebted to aesthetics.

Helmut Swiczinsky, who contributed to major Coop spatial concepts from the UFA Film Palace in Dresden to the BMW World in Munich, had long since departed from building, which increasingly became a real estate business from the cloud. But not from the clouds themselves. And that he now floats among the clouds in sky blue, beyond gravity, is comforting. The rest? Not yet.

Swiczinsky's architectural philosophy centered on the belief that buildings should defy conventional expectations and create spaces that seemed to float weightlessly. His partnership with Prix revolutionized how people thought about architecture in the late 20th century, moving beyond the rigid modernist principles that had dominated the field. Their manifesto called for "blazing wing" architecture that would "burn a hole into the smooth, blue summer sky."

The duo's influence extended far beyond their built works. They organized happenings and performances, wrote manifestos, and challenged the architectural establishment through provocative designs that seemed to ignore the laws of physics. Their early pneumatic structures and temporary installations captured the rebellious spirit of the 1960s while pointing toward a more dynamic future for architecture.

Among their most celebrated projects was the Rooftop Remodeling in Vienna, which appeared to crash through the roof of an existing building like a crystalline meteorite. The design became an icon of deconstructivist architecture and established Coop Himmelb(l)au as leaders in the avant-garde movement. Later works, including the Academy of Fine Arts in Munich and the Central Los Angeles Area High School, demonstrated how their radical vision could be applied to institutional buildings.

Swiczinsky's departure from active practice in 2006 marked the end of an era for the firm he had co-founded nearly four decades earlier. While Prix continued to lead major international projects, Swiczinsky retreated from the increasingly commercial world of contemporary architecture. Those who knew him described a thoughtful, poetic figure who remained committed to the original ideals that had driven the partnership's early experiments.

The architectural community has lost not just a designer, but a visionary who helped redefine what buildings could be and do. Swiczinsky's legacy lives on in the countless architects who continue to push boundaries and challenge gravity, both literal and metaphorical, in their pursuit of spaces that inspire and uplift the human spirit.