Taoism refers to a variety of related philosophical and religious traditions and concepts. These traditions have influenced East Asia for over two thousand years and some have spread internationally.
Taoist temples may fly square or triangular flags. They typically feature mystical writing or diagrams and are intended to fulfill various functions including providing guidance for the spirits of the dead, to bring good fortune, increase life span, etc. Other flags and banners may be those of the gods or immortals themselves.
Taoism Wikipedia Entry