With a  Lopan (Chinese compass ) the main Yang energy known as "The Facing" of the house will be determined. It brings certain "Flying Stars" with it, calculated and based on the Lo Shu chart. The numbers in the magic square move within time frame and certain energy flow.
In a building or any construction, Flying Stars are calculated based on a periodical Qi- energy of  a 20 year cycle. Each cycle identifies the movements of fortunate and unfortunate stars which will bring good or bad luck to the resident of the building. These lucky or unlucky Flying Stars can be also calculated for every month, week and day. This placement of Flying Stars helps to identify the Water and Mountain Stars which indicate the best direction for various combinations of wealth and health.