There are, as of this morning, 634 members of the Hidden Rocks of Vinton, Iowa Facebook page.

Hundreds of kids and parents have been participating in the informal activity since April, and the project continues to grow and the rocks are becoming more creative.

Many rocks have specific themes or messages; many in the group are also discussing ways to make more creative rocks.

On Sunday morning, Benton County Deputy Dave Upah walked in the back door of the Benton County law enforcement center and found a rock with a “Thank You” message on it.

“It made my day,” Upah wrote as he shared the photo of that rock on Facebook.

Anyone is invited to paint, find, and re-hide rocks and to take photos of all of those activities, and to share those photos on the Facebook page.