故旧

故 = 古 + 攵 : Mnemonic symbol: This character only appears in 做, so we don't need a strong mnemonic symbol. We should be able to refer to 故 when we think of 故事 or 故意. Because it fits nicely to its components, I'll think of it as in the meaning of 故墓, an old grave.

故 = 古 + 攵 : There is an ancient cloister in the space station's bathroom, and Gitta Giraffe once heard a story from her fellow astronauts that there's an old tomb inside with lots of treasure. One day she can't hold herself back anymore and deliberately breaks the cloister open using a sledgehammer.

旧 = 丨 + 日 : In the year 2076 Joan of Arc (ji) and the sun (日) meet again in the outhouse's bathroom (ou4). They are both very old (旧) and have to use dinosaur bones (丨) as crooks.