- The mirror - heartshaped and made of highly polished steel.

It is said, "They are built in convenient places where one who had been made mad by the sight of a spirit or demon might glance into the mirror and be immediately healed."  When elements from the collective unconscious broke into one's conscious sphere in the form of what was called a demon or spirit, looking into the mirror acted as a form of concentration.

The image in the mirror is a reflection of conscious reality, with its necessary limitations.  

In this way it helps to reinforce the protective circle around the person.