介

Top indexing person radical 人 (Kangxi #9) - frontal stance of a standing figure. Carries the meaning core: a 介 was originally a person standing between two armoured plates (the lower strokes), so 'situated between' is the action of the figure. Same radical anchors 个, 今, 从, 众 - all human-position characters.

Bottom two short verticals - abstract markers depicting the two armour plates strapped to the front and back of the figure above. The original 介 was a soldier in mail; from 'enclosed in armour' came 'shell' and 'situated between' (sandwiched between plates). Pure ideograph role: these are positional indicators, not freestanding characters.