GTA V- Stone writing (easter egg)

Description YT

I came across this easter egg (I think) on my was to my safe house. You should go check it out and tell me if I'm missing anything els, maybe there's more of these stone writings all over the map, idk, commect if there is. But seriously, there might be other parts to this, maybe its linked to a big easter egg, idk you tell me. Ill keep on looking for more.