5. Cheonbugyeong_cheon yi sam ji yi sam in yi sam

[天二三 地二三 人二三]
[천이삼 지이삼 인이삼, cheon yi sam ji yi sam in yi sam]
Based on Two, Heaven circulates under Three. 
Based on Two, Earth changes under Three.
Based on Two, Humanity creates under Three.

What is the underlying principle that equally applies to all creation and transformation in Heaven, Earth, and Humanity? It is the function of Three within Two.