The modern yin-yang symbol, which was known as the taijitu in the earlier ages, was ...

... first introduced by by Song Dynasty philosopher Zhou Dunyi (1017–1073) and later depicted by Zhao Huiqian (1351-1395 CE), entitled Tiandi Zhiran Hetu (Heaven and Earth’s Natural Diagram of the River). It is a little odd to find this symbol on the ground of a Balinese ashram, but shows how universal it became ☯