It is fairly common to see painted rocks along rail-trails in northeastern Pennsylvania. Some are painted by children, others are a hobby of adults. Many of the ones pictures below seem to be from high school students possibly as an art assignment. I am just speculating about the latter. I always find these as a pleasant surprise. The best part is less the stones and more the fact that someone took the time to improve the trail experience.
Please comment if you have seen painted rocks along the trails you frequent.