If you don't have this in your area then start it! Find some rocks and paint them then hide them in public places. People of all ages (but mostly kids!) get a thrill out of finding them and reading the message on the back. It's a great way to get creative as a community and add little pops of art and creativity to boring spaces.
Any paint will do but for younger kids who are more likely to taste paint, try getting some FAS non toxic paint. Have fun binding them in nature together and talk about who might find them. This is a fantastic activity for language development.
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