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).
兼
=
秝
+
肀
:
Mnemonic symbol: a double. Joan of Arc (ji) and her stunt double (兼) are eating two bowls of cereals (秝) while the real Joan of Arc signs autographs with her crayon (肀) in front of the anthill (an1).