Natural revelation is the revelation of God in nature.  Rom. 1:20 says, “For since the creation of the world His invisible attributes, His eternal power and divine nature, have been clearly seen, being understood through what has been made, so that they are without excuse.”  Nature can tell us certain things about God.  Since nature is ordered, we can conclude that God is ordered as well.  Since the universe is well-balanced we can see that God is wise.  Furthermore, we can see reflections of the Trinity in creation.  For example, time is past, present, and future.  Space is height, width, and depth.  Matter is solid, liquid, and gas.  So, we can see a trinity of trinities, and it is reasonable to conclude that the created order reflects the Creator himself who is a Trinity.