SOUTH KINGSTOWN, R.I. (WPRI) — For the past thirteen years, glass orbs have been hidden around Block Island. They're free for the taking, but you have to find one first.

Eben Horton created the Glass Float Project in 2011. His wife Jennifer Nauck has been helping him since 2012.

Every year, the pair creates 550 glass floats, which are then hidden by a number of people around the island.

"They're hidden on Block Island on the beaches and the greenway trails," Horton said.

Glass floats have been around for a long time. Nauck explained that "they're modeled after Japanese fishing net floats."

"So these are things that people have been finding on the beaches for hundreds of years," Nauck added.

The floats are etched with a date and a registration number so people can report their finds.

Horton came up with the idea for the project many years before it came to fruition.

"When I was 19 years old, I was working at this glass studio and a bunch of pieces of glass had little cracks in them. They couldn't sell them, and I thought, these are too cool to throw away," Horton recalled.

Watch how the glass floats are made. This story continues below the video.

"So, I took all this glass and hid them all over Middletown and Little Compton, and that idea stuck with me for a long time," he continued.

The project blew up. Native Block Islanders and tourists alike search for the orbs every summer. People have come all the way from India just to meet Eben and try to find an elusive float.

"It's very humbling. I never ever would've thought when I hid the first ones that it would become what it has," Horton said.

There is an etiquette to the search. The floats are never hidden in dunes, up bluffs, on school grounds, on private property or in cemeteries.

The floats will always be hidden near established trails. There is no need to deconstruct stone walls or damage the natural landscape.

Another guideline: once you find a float, don't take any additional ones home.

This year, there will be 24 special floats that are different colors for people to find.

The glass blowers have some tips for finding the floats.

"Whatever catches your eye could be a potential hiding place," Nauck advised.

"Where would you hide it? I'd hide one there, well, maybe he did," Horton added.

So keep an eye out if you're walking on a Block Island beach or trail this summer. You may just find some hidden treasure.

Have you found a glass float? Send us your pictures here and check out these float finds.