Blink and you’ll miss it — what’s being touted as the largest art project in NYC history lasted just shy of two hours.

Organizers say the “Pi in the Sky” installation — which wrote the first 314 digits of the mathematical constant “Pi” in skyscraper-sized characters over New York City — was visible for more than fifteen miles in all directions.

The project inspired thousands of tweets under the hashtag #piinthesky on Saturday afternoon — and caused thousands of folks gaze skyward in confused fascination.

“It was really inspired by impossible thinking,” creator Ben Davis, 53, founder of the San Francisco-based collective Illuminate the Arts, said as he stood in Central Park’s Sheep Meadow watching the puffs of smoke dissipate.

“I wanted to take this phrase that meant impossible, and make it real.” Davis said of the installation, which the collective debuted in in San Francisco,

The collective aims to create “radically accessible public art,” he said — and with a potential audience in the tens of millions, Pi in the Sky certainly fit the bill.

Although the intent of the gargantuan display was not immediately clear to many of the observers who commented on Twitter, Davis says that was part of the point.

“Pi is a mysterious number, an irrational number; I want people to have a moment of wonder,” he said.

He went on to mention “The Gates” in Central Park, which lasted for just two weeks in 2005, and remarked that “the soul of the art is not determined by the life of the art.”

Davis partnered with a New York advertising agency, AirSign Inc., to create the display in time to coincide with “Manhattan-Henge,” the time each year when the sun lines up with the borough’s street grid.

“There were a lot of technical hurdles,” said ad man Patrick Walsh, 33, who worked with the artist. The project required five computer-synchronized planes flying at 10,000 feet.