The latest craze sweeping the toy world, the fidget spinner, was developed in response to rock-throwing by Palestinian youth.

Twenty years ago, while on a visit to Israel, Catherine Hettinger heard about Palestinian youth throwing rocks at Israeli police and civilians. She came away from her trip with the idea for a toy that could offer a soothing distraction for children.

“It started as a way of promoting peace, and then I went on to find something that was very calming,” Hettinger told CNN Money in an interview on Monday.

After Hettinger’s patent on the toy expired in 2005, toy companies went on to develop the product, and this year it took off.

“Maybe if it was some kind of exploitative product — like a new style of cigarettes — and my only motivation was to make money, I’d have a different attitude.”

The spinner is made from either plastic or metal and consists of two or three prongs with a center bearing. An individual holds the center while spinning the prongs. The toy is designed to act as a release mechanism for nervous energy.

“When you start seeing these things flying off the shelf at your local 7-11, you know things are heating up,” said Hettinger, who lives in Orlando, Florida.

Hettinger’s patent was approved in 1997, four years after her first fidget spinner was introduced, but her version of the product did not take off despite her efforts to sell it to toy companies.

Toy giant Hasbro initially rejected her proposal, but now, almost 20 years later, sells the widely popular device.