The palm-sized rocks look perfectly ordinary, at first.

Yet with just a few dabs of paint and some kind words, they’re transformed into the hide-and-seek reward of a treasure hunt that’s spreading across the north metro area.

For months, the rocks have been popping up in little libraries, on park benches and outside shopping centers, largely thanks to an area Girl Scout troop that has painted and hidden hundreds of them since April.

Their efforts are part of the Kindness Rocks Project, a movement that got its start on the East Coast two years ago and has now spread across the globe, with painted rocks popping up from Europe to Australia.

They often bear simple messages, like “Be Kind” or “You are loved.” A small, wordless picture may also convey encouragement.

“When somebody finds a beautifully decorated rock, it can make them happy,” said 9-year-old Alyx Gerhart, a member of Girl Scout Troop 16984. “We’re spreading joy.”

The idea is that even an unassuming rock can offer a sign of human connection and inspiration. Those who find the rocks are then encouraged to paint and hide their own.

“It’s not really about the rocks,” said project founder Megan Murphy, a 49-year-old life coach who lives on Cape Cod in Massachusetts. “It’s all about connecting people with one another.”

Since Murphy first started inscribing messages on rocks and placing them around Cape Cod, the project’s Facebook page has amassed nearly 50,000 likes, with the hashtag #thekindnessrocksproject rippling across social media.

“I never in my wildest dreams expected that it would get to this,” Murphy said. “It’s just kind of created this energy of its own.”

Many towns or regions have their own Facebook groups, where members often share rock photos and uplifting stories. The “North Metro Rocks” group has so far attracted more than 300 members.

Mindy Gibeau, a co-leader of the Girl Scout troop behind the effort, first learned of the movement from a friend in Florida.

The troop is made up of 14 girls, ages 9 to 10, and Gibeau thought the project was an ideal way for them to get involved in their communities as they work toward earning their Bronze Award, an important honor for a Girl Scout Junior.

“It’s just about kindness,” said Gibeau, whose daughter is in the troop. “It’s something that families can do together.”

On a recent evening, the Girl Scouts hosted a painting party in Champlin, drawing more than 30 people to a park pavilion to beautify unadorned rocks.

Gibeau and Kristen Brisky, who also leads the troop, shared tips and art supplies as participants got busy at picnic tables.

Parents said the project helps fight summer doldrums and gives kids a reason to explore local parks.

“It gets the kids outside in the summertime,” said Travis Sorenson, who attended the painting party with his wife, Jolene, and their three boys. “It makes them look around.”

The Girl Scouts plan to keep decorating rocks through the winter, with the hope that more people join the hide-and-seek movement.

“There’s no end in sight,” Brisky said.