“Fences, unlike punishments, clearly mark out the perimeters of any specified territory. Young children learn where it is permissible to play, because their backyard fence plainly outlines the safe area. They learn about the invisible fence that surrounds the stove, and that Grandma has an invisible barrier around her cabinet of antique teacups.”
Source : Jeanne Elium, Don Elium (2011). “Raising a Daughter: Parents and the Awakening of a Healthy Woman”, p.155, Celestial Arts