燕

Bottom 灬 - the four-dot bottom form of 火, but here it isn't fire at all. The dots are a graphic substitute for the swallow's forked tail feathers, an accidental homophony of shape that lets 燕 share an indexing radical with cooking characters like 煮 and 蒸. Etymologically the dots are tail; positionally they index as the fire radical.

Top 廿 - visually the number twenty, but in 燕 it has nothing to do with counting. It is a graphic stand-in for the swallow's small flat head and pointed beak, the topmost slice of the original bird pictograph that gave rise to the modern character.

Middle 口 - not a literal mouth here, but the stylised body of the swallow seen from below. The whole top stack 廿+口 traces the bird's head and belly fused into one silhouette; the original oracle-bone graph showed a swallow in flight with wings spread.

Middle-bottom 北 - depicting the swallow's two outstretched wings, beating away from the body. 北 is itself a pictograph of two people back-to-back; reused here purely for its winged shape, a happy coincidence between two unrelated graphs.