In the old days - like maybe 10 years ago - people who wanted to start a business would rent an office, hang out a shingle, hire a receptionist, and get down to work. Now, people of an entrepreneurial persuasion launch a start-up, join a co-working space, and find collaborators, often while making coffee in said space's communal kitchen.

The way we work is changing, so it makes sense that the architecture of work would change, too.

Instead of building downtown office towers the way we once did, Philadelphia has been exploding with co-working spaces, places where you can rent a desk, a conference table, and a Wi-Fi connection by the day, week, or month. There's Culture Works, Indy Hall, Benjamin's Desk, Pipeline - just to name a few. Yet many of the shared office spaces still tend to be housed in button-down Center City office buildings.

The University of Pennsylvania's new Pennovation Works offers an intriguing contrast to the standard co-working fare. Located in a former industrial park at 34th and Grays Ferry Avenue, the campus contains a plentiful and eclectic mix of cheap buildings: conventionally partitioned offices, wet labs, soaring factory floors. There's plenty of room for small companies to scale up.

The complex - a contraction of Penn and innovation - also boasts spectacular views of the Center City and University City skylines. Once a DuPont plant, the 23-acre complex sits on the Schuylkill next to the Grays Ferry Crescent, a completed segment of the Schuylkill Banks. Because Pennovation is on the east side of the river, near the Grays Ferry Pathmark, you can imagine its being absorbed someday into the orbit of Greater Center City.

For now, though, the offbeat location is Pennovation's biggest drawback. While it's technically only a 15-minute walk to the center of the Penn campus or the South Street Bridge, the complex feels a world away from the city's coffee-and-craft-beer zones. "It's psychologically distant," concedes Anne Papageorge, Penn's vice president for real estate.

To help put Pennovation on the city's co-working map, her staff has hired a slew of high-profile architects and consultants to rethink the complex, including HWKN, Land Collective, WRT, KSS Architects, and Bruce Mau Design. Their conclusion, essentially, is that Pennovation should define itself as a funkier, cheaper alternative to the University Science Center, which also rents labs and offices to start-ups, but at Center City prices.

That means working with what's already there, rather than constructing expensive new buildings the way the Science Center does. For its first effort, Penn is renovating a classic brick-and-concrete factory next to the river that it's calling Pennovation Center.

Such manufacturing relics are a favorite of start-ups because their open-plan spaces are so flexible. At the same time, these factory spaces have become something of a start-up cliché. The trick, as HWKN's Matthias Hollwich explains, "was to reformulate it into something special."

Hollwich, a New York-based architect who spent four years working for Rem Koolhaas, has been making a career out of tweaking the ordinary. To help us see this common building type afresh, he came up with a design that disrupts the familiar factory grid. He cracks open the brick-and-concrete wall at the far end of the building and, in its place, attaches an unlikely, faceted glass nose.

That striking addition will not only give the building a modern identity, but it should also make it a better, more inspiring place to work. Three stories high, the crystal nose allows light to flood the building, while opening views of the two skylines.

It also fulfills a symbolic purpose: The nose serves as a giant arrow, pointing the way to the city's business heart, making Pennovation feel closer to the action. Hollwich says he likes to imagine the creative types who will occupy the building doing practice pitches while standing in front of the glass structure, with the skyline as a backdrop.

What's unusual about the dramatic addition is that it's located on the back of the building. You won't see it when you first enter the Pennovation complex.

No matter. Hollwich has other ways of signaling to prospective tenants that changes are afoot. The first is the building's new entrance, a three-story, glass-faced isosceles triangle, cut sharply into the building's grid. And, in homage to the inventive legacy of such companies as Apple and HP, he plans to install garage doors at ground level on the east facade.

Because the Pennovation site is such a mishmash of buildings, the university also felt it was important to create a campus feel on the site. The landscape design, by David Rubin of Philadelphia's Land Collective, was developed in sync with Hollwich's renovation of the factory.

As you approach the complex from Grays Ferry Avenue, you'll be welcomed by a gracious plaza, shaded by sycamores and outfitted with clusters of tables. Rubin plans to celebrate the factory grid by planting tall, straight poplars around the perimeter, guiding the eye to the nose cone at the far end of the building.

He likes the idea that the dramatic addition is hidden: "It's as if the social energy of the space pushes through the building and explodes out the back."

According to the master plan by WRT, the edge of the site along the river is meant to be used for future construction. Right now, it's a glorious, wide lawn that slopes to the river. Rubin has designed two diagonal paths to take people to the water's edge.

Although construction on the $37.5 million landscape and renovation won't be finished until mid-2016, Penn has already begun leasing space to start-ups, including KMel Robotics, which makes small, flying quadrotors - something like drones.

Even with all the available space on the Pennovation campus, KMel needed an outdoor area to test its flying robots. The architects' solution was to build what looks likes a net-covered batting cage between the plaza and renovated factory. Tenants can watch the robots flit around while working on their laptops and experiments.

That's something you can't do in just any co-working space.