Under one fung shui principle, the living space of a home is divided into nine sectors (eight cardinal and inter-cardinal sectors and the centre). Family members are then linked with a specific sector. For instance, the father is associated with the northwest sector, the mother with the southwest and the youngest daughter with the west. Thus, if the northwest sector is 'missing', the head of the household might encounter professional or health problems. However, if the northwest sector has a protrusion that makes it slightly larger than the others, this augurs well for the patriarch's prospects. After applying this principle to modern living, one can understand why fung shui masters recommend residences of a regular shape. A sector is considered missing when it is less than two-thirds the size of the other sectors, so do not be overly concerned if there are slight differences in surface area between sectors in your home. One school of thought states that missing sectors may hinder certain aspects of your life (for example, romance or wealth), but this is not a traditional principle. If you encounter difficulties in an irregularly shaped residence, enlist the help of a professional. Simplistic solutions, such as covering a wall with mirrors to expand the missing sector, may not work.