Sometimes, form follows fortuity. In the 1990s, Rem Koolhaas developed an idea for a private house near Rotterdam; when that project was shelved, he adapted the concept to a much larger building — a concert hall in Porto, Portugal.

Now, Joshua Prince-Ramus, who had been a partner with Koolhaas at OMA, has pulled off an even more audacious “reuse” of a cancelled project. Asked to design a fashion-company headquarters in Istanbul, on an impossibly tight schedule, Prince-Ramus made use of plans he had originally developed for the Annenberg Center for Information Science and Technology at the California Institute of Technology, in Pasadena. The Caltech project had been called off just before construction was set to begin. Prince-Ramus says that if there is a wariness among architects about reusing designs, there shouldn’t be. “It’s not about copying,” he says, “but about advancing an idea.”

To the owners and employees of the Vakko Fashion Center, what matters is that REX Architecture, Prince-Ramus’s Manhattan-based firm, produced a spectacular building — and did it in less than a year. Even more remarkably, it was built using a structure that had been intended for a hotel, but abandoned some 20 years earlier. (In Turkey, speculative building sometimes means starting a project and seeing if it succeeds — and just walking away if it doesn’t, Prince-Ramus explains.) Incredibly, the existing concrete structure had almost precisely the same dimensions, both in plan and section, as the building Ramus had designed for Caltech.

In each case, Prince-Ramus’s parti consists of a simple, three-story rectangular doughnut with a ground-floor arcade. In the center of the doughnut, and structurally independent, rises a set of steel-framed boxes that tilt upward, providing vertical circulation and some excitingly eccentric spaces. At Caltech, where the administration required a sober exterior, “We called it ‘the wolf in sheep’s clothing building,’ ” Prince-Ramus says. (There, the interior spaces, the “wolf,” included classrooms, lounges, and exhibition areas.) At Vakko, the feral spaces include showrooms, conference rooms, a 200-seat auditorium, and a small fashion museum; many of these areas sport mirrored surfaces that create kaleidoscopic effects. “It’s like the baby bursting out of Kane’s stomach in the movie Alien,” says Prince-Ramus, describing the contrast between the restrained perimeter and the apparent chaos inside.

The Vakko project began when the company’s owner, Cem Hakko, learned that the Turkish government planned to raze his company’s existing headquarters to build a highway interchange. During New York’s Fashion Week in February 2008, he interviewed architects, hiring REX (then a partnership of Prince-Ramus and Erez Ella) practically on the spot. Hakko told him the building had to be designed and built within a year, but not to worry, because there was an existing structure to work with. Prince-Ramus gulped, assuming the existing structure would make his job harder, not easier. But on a trip to Istanbul a few days later, he discovered the uncanny similarities between it and the proposed Caltech building.

Less than a two weeks after meeting Hakko, Prince-Ramus put in the steel order for the building’s core: boxes designed so that they could be freely oriented, even tilted to provide vertical circulation, after they were built. This strategy, Prince-Ramus says, gave him six weeks — while waiting for the steel to be delivered to the site — to “devise the composition of boxes that best resolved the buildings’ programmatic requirements.”

In another piece of good luck, the old hotel foundation included a large underground parking garage, and Power Media, Vakko’s sister company (sometimes called the Turkish MTV), needed soundproof and lightproof studios. Prince-Ramus repurposed the subterranean spaces for Power Media, even turning what would have been an outdoor swimming pool (set within the garage space) into a landscaped courtyard. So ingenious was Prince-Ramus’s reuse of the garage that Power Media was able to move into its space while construction of the above-ground portion of the building was still in its early stages.

Long interested in bending glass to increase its strength, Prince-Ramus had an X-shape slumped into each of the facade’s large panes. The stiffness provided by the Xs meant the glass could be thin (3⁄16 inch) and light enough to be held to the concrete floor plates with corner pins. Supple and lacking mullions, the skin suggests a building covered in Saran Wrap.

Turkey, which Prince-Ramus calls “a country going through its industrial revolution,” retains many of its old construction trades, so the architect had no trouble finding craftsmen to make the jigs on which the glass was slumped. “Other fully industrialized countries would no longer have had the craftsmen capable of such precision,” he says.

But the playfulness of the facade barely hints at the surprises in the middle of the building, which explodes with the kind of exuberance reminiscent of Koolhaas and Prince-Ramus’s Seattle Public Library. The boxes, bolted together on-site and lifted by crane into the doughnut hole, include (from bottom to top) the fashion museum; an auditorium; a series of stepped showrooms; and, finally, offices for Vakko executives, from which they can descend onto a wraparound terrace with a mirrored ceiling. What looks, from the outside, like a fairly conventional three-story building, feels expansive inside — thanks to the incorporation of underground space, the disorienting effects of the angled boxes, and the multiplying effects of mirrored surfaces.

For Prince-Ramus, the building offers a lot of symbolism. A gutsy decision by a client to create a showplace out of essentially detritus (a long-abandoned structure) says a great deal about the possibilities of adaptive reuse. And because the building recycles not only a structure, but an idea developed for another place and purpose, the project has special meaning in a time of recession. To Prince-Ramus, who split from OMA in 2006 and has endured the ups and downs of any young practitioner, the experience offers a lesson: “If you’re developing an idea, don’t ever believe it’s dead.”