On a cloudy day this May, in the dull fluorescent light of a plain white Google conference room, Rafa Camargo, Richard Wooldridge and Blaise Bertrand told CNET their plan to disrupt the phone market.

Ara, a Lego-like phone with modular parts, would let buyers snap on a better camera, additional batteries or any other creative hardware a developer might dream up. It was set to be the first phone entirely designed by Google, the three men claimed.

Then the Ara project was abruptly shelved.

But now, all three of those men work for Building 8 -- a secretive new division of Facebook. There, they've been joined by an impressive list of heavy hitters that reads like a who's who of the tech world: Motorola, Tesla, Apple and Amazon, in addition to that contingent of Google ex-pats.

James Martin/CNET

So what, exactly, is this superteam of designers, engineers and manufacturing experts working on? Nobody outside of Menlo Park knows for sure, but the hires -- and at least one under-the-radar acquisition -- seem to indicate two things: it's mobile, and it may be modular.

Whatever it turns out to be, building hardware at this scale represents a major shift for Facebook. The company's first attempt at hardware -- a 2013 joint venture with HTC that became known as the " Facebook phone" -- was a fiasco, discounted to 99 cents mere weeks after its debut. Since then, though, the company has doubled down, first with its $2 billion purchase of VR headset maker Oculus in 2014, and now with what appears to be a far more ambitious hardware endeavor with Building 8.

What's Building 8?

Originally, it sounded like Building 8 was a skunkworks where Facebook could prototype a whole bunch of new technologies -- like 360-degree video cameras -- and figure out the fastest way to get them into consumers' hands, usually through partnerships.

Enlarge Image Google Maps

That's what Facebook CTO Mike Schroepfer suggested to the The Wall Street Journal, and it's what was widely assumed when Facebook CEO Mark Zuckerberg announced he'd hired Regina Dugan to lead Building 8. Dugan is the former head of both the US Department of Defense's DARPA research arm, and Google's Advanced Technologies and Projects (ATAP) research lab.

Zuckerberg suggested, in an April 2016 blog post, that Building 8 would pursue "augmented and virtual reality, artificial intelligence, connectivity and other important areas" -- which sounds pretty sciencey, to be sure.

But the division's job postings and recent hires tell a slightly different story -- beginning with the Building 8 mission statement you'll find at the top of each job post.

Here's the mission statement in full:

Building 8 brings together world-class experts to develop and ship groundbreaking products at the intersection of hardware, software, and content. We have a clear mandate to ship products at scale. In particular, seemingly impossible products that define new categories that advance Facebook's mission of connecting the world. The B8 team will apply DARPA-style breakthrough development at the intersection of ambitious science and product development. It will operate on aggressive, fixed timelines, with extensive use of partnerships in universities, small and large businesses.

Building 8 is all about shipping hardware, it seems. And could "seemingly impossible products" include an ambitious modular phone like Ara?

Facebook didn't reply to a request for comment.

Phone experts wanted

CNET analyzed nearly 50 Facebook job postings, past and present, and dug through dozens of employee profiles on LinkedIn to see the big picture. It soon became clear: Facebook isn't just building a lab in hopes of spinning out a few new startup companies.

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Instead, Facebook is hiring over a dozen different heads of what appear to be a dozen distinct departments within Building 8 -- including industrial design, mechanical engineering, electrical engineering, device software, applications and services, manufacturing, supply chain and even customer service. Many of those heads of product are being asked to hire their own teams from scratch.

In other words, Facebook appears to be building an organization that could conceptualize, design, produce, ship and sell hardware, and even deal with customers after the fact. (Who needs customer service and return policies for prototypes?)

Only two of Facebook's new department heads are devoted to "skunkworks" and "partnerships," respectively, and few of the job postings ask for experience across the wide range of disciplines you might expect for a research lab.

But many of them ask for people with mobile experience -- Android in particular.

For instance, this posting for a lead electrical engineering systems architect specifically asks for experience with mobile processors, antennas and thermal design, and these two for a camera software engineer and a kernel software engineer each require five years of experience working with mobile processors and an "understanding of Android Frameworks."

The heads of product software, product engineering and hardware each need experience leading teams that have brought "smart phone (Android, iOS) and/or consumer electronics" to market.

There are also strong hints that the new head of software applications and services will be tasked with developing Android apps for the hardware Building 8 will make.

Two other jobs specifically mention Facebook's intent to build "compelling consumer-facing products on the Android platform," and yet another hints that Facebook may sell accessories to go along with its products.

Now playing: Watch this: Inside Facebook's new hardware lab

Above: Facebook's new Building 8 hires will have access to Area 404, a 22,000-square-foot hardware lab inside Building 17 at Facebook's Menlo Park headquarters.

Key talent

According to their LinkedIn profiles, many of Building 8's recent hires reinforce the idea that Facebook is pursuing hardware in a big way:

Nathan Kelly, Building 8's new head of global supply chain, previously helped build supply chains for Sonos, Tesla, HP/Palm, Microsoft and Sony Ericsson, according to his LinkedIn profile.

Rich Heley, the new head of manufacturing, spent a decade at Apple figuring out how to mass produce aluminum enclosures for the iPhone, iPad, iPod and Mac -- all the way back to the first MacBook Pro -- then spent three years at Tesla, finishing as VP of product technology.

Furhan Zafar previously directed the supply chain for Motorola's Moto Maker -- an effort that let buyers pick different phone backs and different accent colors for their phone's buttons and grills before they shipped to customers.

Tim McCune, Building 8's new head of systems engineering, spent 17 years at Motorola and a brief stint at Apple as well.

Richard Wooldridge, the new COO of Building 8, wasn't just the logistics behind Google's modular Ara handset -- he also spent four years leading the global supply chain at Motorola, including Moto's effort to build a factory in the US for the first Moto X phone.

Rafa Camargo, Building 8's new head of product engineering, led development on Google's Ara phone, after a year and a half at Amazon's Lab126 hardware group working on the Amazon Fire Phone and 13 years at Motorola on such iconic projects as the Droid, Razr, even the StarTAC flip phone.

Viresh Rustagi, the new head of device software at Building 8, was the head of software for Google's Ara as well -- after a two-year-plus stint managing a software dev team for Amazon's Kindle Fire tablets and set-top boxes, and 12 years working on software for mobile processors at Broadcom.

Blaise Bertrand, Facebook's new head of creative, spent three years designing for Motorola and 12 at noted design firm IDEO, in addition to seven months at Google ATAP working on the Ara phone.

These high-level execs are just the start. Building 8 has also snapped up a number of former Apple employees, including an executive recruiter, and is currently hiring three other recruiters and a recruiting manager to expand its collection of talent.

It's also worth noting that, for now, all of these hardware efforts appear to be separate from the ones inside Facebook proper: the company already had its own VP of hardware and supply chain to help build its data centers and networking infrastructure. Oculus, the Facebook virtual-reality subsidiary, has its own separate hardware team too, plus its own research arm based in Seattle.

Now playing: Watch this: Project Ara: Google's vision for the future of the smartphone

Above: Rafa Camargo explains the vision for Google's Ara phone in May 2016.

Will Google's modular phone live on?

Even if Facebook just hired four key members of the Google Ara team to lead its manufacturing and supply chain efforts, and even if it has a number of other mobile experts on the payroll, we can't say for sure they'll be working on a phone.

All of Facebook's new expertise could go towards anything else that uses mobile processors, radios and the Android OS -- such as headsets, tablets, watches, smart home and other internet-of-things devices. Or something entirely new.

And even if it is a phone, it isn't necessarily a modular one. Having failed to convince Google, the team may have given up on that idea.

But perhaps not: In September, one month after the Ara team jumped ship, Building 8 bought a hardware startup called Nascent Objects -- which just so happened to be developing a modular consumer electronics platform, too.

At the time of the acquisition, Building 8's Dugan implied that Nascent's tech would be used for fast prototyping: "Imagine designing, building and delivering a hardware product in just weeks. Instead of months, or even years," Dugan wrote on her Facebook page. "Together, we hope to create hardware at a speed that's more like software."

But perhaps Dugan meant that Nascent's modular tech could help consumers build their own hardware -- the same idea behind the Ara modular phone.

Back in May, in that Google conference room, the ambition behind Ara was huge. "We want to create a hardware ecosystem on the scale of the software app ecosystem," said Camargo.

Wooldridge promised his team would provide hardware and technical support, and help indie hardware designers get their snap-on modules certified by federal regulatory agencies, so that even a "bedroom student" could add a new feature to their phone.

Enlarge Image Sean Hollister/CNET

Bertrand explained how fashionable it could be, and how attractive for big brands, to have decorative phone pieces that a user could change on the fly.

Now, they're all together again, inside a company that -- unlike Google -- wouldn't be disrupting its own business by competing with existing Android hardware partners. (Facebook is a must-have app on more than a billion people's phones, but the company doesn't make any mobile hardware yet.)

Plus, they're leading a division with access to "hundreds of millions of dollars" over the next few years, according to Zuckerberg.

The ultimate pivot

It's possible that Facebook's hardware ambitions never see the light of day. Consider Apple's secretive Project Titan program, which reportedly staffed up and spent millions on a self-driving car initiative that, so far, has only produced several rounds of layoffs and strategy changes. Reportedly.

But it seems, at least, that Facebook is following the same path as its arch-rival, Snapchat. Until a few months ago, Snapchat's social app was its only product. But the company recently rebranded itself as a camera company and surprised the world with Spectacles, a Snapchat-specific hardware product it had developed in secret (after stealthily hiring its own group of wearable tech experts).

Facebook has a bigger user base than Snapchat, more money and more hardware experts. If the company unveils its own phone -- or mobile accessory -- in the next year or two, it wouldn't be too surprising.

Disclosure: Sean's wife works for Facebook as a business-to-business video project coordinator.