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).
闲
=
木
+
门
:
In her free time (闲) Marie Curie (xi) likes to sit in the anthill's kitchen (an2) to watch her trap door (门). She installed it right under a Christmas tree (木) so whenever someone puts a present under the Christmas tree, shortly afterwards it will fall through the trap door in Marie's secret chamber.