Three mysterious structures that appeared on the water in California and Maine have the tech world abuzz.

Each of the boxy structures sits atop a barge and looks like a four-storey building made up of metal boxes. Little is known about them, but they appear to have been registered by someone familiar with geek speak — and with a sense of humour.

The structures are registered with a Delaware corporation as BAL0001, BAL0010, BAL0011 and BAL0100. In binary code used in computing, the numbers represent "one," "two," "three" and "four." Currently, Nos. 1 and 2 are on the water in San Francisco and No. 3 is in Portland Harbour.

Online speculation has focused on Google Inc., which has a patent for a floating data centre that uses ocean water for cooling. Neither Google nor the company outfitting the vessel shed any light on the matter Tuesday.

Company named after WALL-E corporation

Sharon Gaudin, a writer for the technology website Computerworld, told the Portland Press Herald that the way the vessels were named suggested a technology origin or use.

Barges-San Francisco

Another one of the floating structures docked at Treasure Island in San Francisco. (Jeff Chiu/Associated Press)

"That's a little telling," she said.

Also, the Delaware company to which they're registered is called Buy and Large, a likely joking reference to "Buy N Large," the fictional mega-corporation in the 2008 animation film WALL-E.

While the floating structures might one day have a high-tech purpose, their construction appears to be fairly low tech. They consist of shipping containers welded together and placed atop barges.

Elaborate marketing ploy?

Some reports have also speculated that the barges could be floating Google Glass stores and marketing centres that will be hawking the augmented reality glasses up and down the U.S. coasts.

An official with the San Francisco Bay Conservation and Development Commission told local CBS affiliate KPIX 5 that Google had made inquiries with the agency about setting up operations on the water but has not specified what the operations would be used for and has not actually applied for a permit.

It's uncertain whether San Francisco authorities would even give Google the necessary authorization to operate the barges in the Bay.

"The law is crystal clear in this case: the Bay is not to be used for something that can be built on land," the commission's executive director, Larry Goldzband, told KPIX 5.

With files from CBC News