Well done! I like that you included the photo of you and your son. The stacked stones would be a great find while out walking. I have never encountered anything like that on our walks, but, I have seen little collections of painted rocks with the invitation to take one to keep or to place in a different place for someone else to find.
@digigrandma ... this path is not all that far from your house. It's near the Jerry's off Anderson Lakes (and 169). The Anderson Lakes Parks Preserve. It was a fun find. There were a ton on the path!