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).
肥
=
巴
+
月
:
Frankenstein's Monster (f) and the moon (月) have been eating lots of lollipops (巴) in the Eiffel Tower's kitchen (ei2) until they became round and fat (肥).