Shake: Thunder rises from below, shaking and stirring things up. Shake begins the yang hemicycle by germinating new action… Shake stirs things up to issue-forth.
This passage defines Shake as the fundamental I Ching trigram representing initiatory yang energy — a germinating, upward-thrusting force that disrupts quiescence and inaugurates new cycles of action.
, I Ching: The Classic Chinese Oracle of Change, 1994thesis