An ancient pictograph of a frontal person with the legs crossed at the calves - top dot-and-horizontal the head and shoulders, four lower strokes the two legs interleaving. From limb-crossing came every sense of 交: meet, exchange, hand over, mutual. Indexed under Kangxi #8 亠 (tóu, lid) - just the figure's head-stroke.
Filed under radical 亠 (tóu, #8) by convention. 亠 is not a separate component in 交, so no strokes are highlighted.
