From the Yijing (《
易经》, Book of Changes) cosmogony:
太极生两仪 (tàijí shēng liǎngyí) — the Supreme Ultimate produces the Two Forms (yin and yang). The full sequence is
太极 →
两仪 →
四象 →
八卦, generating progressively more differentiated patterns. Foundational to Chinese metaphysics.