亻
=
丿
+
丨
:
Mnemonic symbol: Rosa Luxemburg. She's quite radical, and her name starts with "r", just like "ren2". Also, 亻appears at the left-hand side of characters, and Rosa is a leftist as well.
Robinson Crusoe (r) and Rosa Luxemburg (亻) are having their favorite snacks in the encampment's kitchen: Rosa is eating a banana (丿) and Robinson is eating a dinosaur bone (丨).
甹
=
丂
+
由
:
Pocahontas (pi) is having a great time with a chivalrous knight (甹) in front of the engine ((e)ng1). The knight is wearing a breathing mask (丂) and has to drink all the Cuba libre (由) Pocahontas fills into the mask.