Feng Shui Convex bagua mirror is a mirror which is surrounded by an eight trigrams octagonal shaped wooden frame and a hanging hook provided on back of frame. The Convex mirror that’s curved outward. It is used to magnify the positive chi. These mirrors reverses negative energy or chi flow and expands positive energy flow in the house, shop, office or business. As per feng shui, bagua mirror vastu placement – It should be placed outdoors means above the front door or above a big window that is facing outside, never place indoors.