允

Bottom 儿 - the legs/walking-person radical, the indexing element here. It depicts a person seen from the side with bent knees, often used as a body-base under another component. 允 belongs to the small radical-儿 family with 元 (origin), 兄 (elder brother), 兆 (omen) - all built on the same striding silhouette.

Top 厶 - originally a coiled-arm shape that became the abstract symbol for 'private, oneself.' Some readings of 允 take this as a person's nodding head above the legs below; others see it as a hand pressed to the chest in a gesture of sincere assent. Either way, it pictures the inward acknowledgement that gives 允 its 'permit, agree, sincere' meanings.