之
=
丶
+
Z
:
Mnemonic symbol: Sooo sleepy... "zZz" (the character looks like a "Z"). James II of England (zh) fell asleep in front of the space station (Ø1). He sleeps on a big petal leaf (丶), making loud "zZz" (之) sounds.
外
=
夕
+
卜
:
There's a hole in the wall of the airplane's bathroom (ai4), and from outside (外), a bat (夕) wants to enter. Willy Walrus (w) is very afraid of bats, so he does his best to hinder the bat from entering with a voodoo staff (卜).