可能性

可 = 丁 + 口 : Karl Marx (k) is challenging his abilities (可) in the elevator's living room (e3). He tries to force a nail (丁) into a mandarin (口), just by using his head. On top of that he tries to do so one thousand times, in order to create a bed of nails (mnemonic symbol for 可).

可 = 丁 + 口 : Alternative mnemonic symbol: kebab, from the pronunciation "ke". Karl Marx (k) is preparing a kebab (mnemonic symbol for 可) in the elevator's living room (e3). He also skewers mandarins (口) on the long steel nails (丁) and will only allow (可) his guests to eat the rest of the kebab if they eat their mandarins first.

能 = 匕 + 厶 + 月 : Mnemonic symbol: bicorne hat.

能 = 匕 + 厶 + 月 : Napoleon and the moon are fighting over who's the real Napoleon in the engine's kitchen. They both wield a ladle each. During the battle, Napoleon destroys the moon's fake nose, while the moon dents Napoleon's bicorne hat.

性 = 忄 + 生 : Marie Curie had a strong character since she was little. Even in her cradle in the engine's bathroom she was only playing with a flail.