Hexagram H21 is named 噬嗑 (shì kè), Gnawing Bite. Other variations include biting through and biting and chewing. It may refer to teeth working together to bring coherence.[2] Its inner (lower) trigram is ☳ (震 zhèn) shake = (雷) thunder, and its outer (upper) trigram is ☲ (離 lí) radiance = (火) fire.