俳

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).

非 = 三 + 丿 + 丨 : Mnemonic symbol: a negative film (photography)

非 = 三 + 丿 + 丨 : Frankenstein's monster made an effort to photograph the Eiffel Tower, but now his negative is a big mess. In front of the tower her set up a camera on a Cartesian coordinate system as a tripod, and he attached a banana and a dinosaur bone to the camera so that he can finely tune the angles. All was for naught as he now holds the messed up negative in his hands.