When considering colors for the exterior to the house, use a color that is productive to, or is the same as the house trigram. For example, a Zhen house (sitting east) would be supported by blue (water) or is also strengthened by green, the natural color of the Zhen trigram. A Dui house (sitting west) would be supported by earth tones or can be strengthened by whites and metalic colors (the color of the Dui trigram).