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).
Sherlock Holmes (sh) wants to have a long life, so he decided to just stay in a golden cage (丰) in the outhouse's bathroom (ou4) and has someone bring him longevity peach buns (寿) every now and then. Every time he gets his snack he gives the person the thumbs up (寸).