Luantou refers to the mountain-shaped water potential, which can be seen; And regulating qi is to calculate a certain position according to a certain formula, which is invisible.
Therefore, the outer building head refers to the mountain-shaped water potential outside the house, including other buildings, houses, apartments, shopping malls, roads and so on near the building.
Neiluantou, or Xiaoluantou, refers to the space in the house, the distribution of furniture and so on.