A Tibetan prayer flag is a colorful rectangular cloth, often found strung along trails and peaks high in the Himalayas. They are used to bless the surrounding countryside and for other purposes.
Prayer flags are believed to have originated within the religious tradition of the predbuddhist Bon. In Bon, shamanistic Bonpo used primary-colored [red, blue, green & white] plain flags in Tibet. Traditional prayer flags include woodblock-printed text and images.