永世

永 = 丶 + 水 : Yu the Great just got the most romantic proposal ever! In engine, somebody prepared a water fountain and had a diamond ring floating on a petal leaf float over to her. Unfortunately Yu the Great doesn't know who the ring is from, as her lover drowned in the water fountain earlier that day.

永 = 丶 + 水 : Mnemonic symbol: as the advertisements tell us, diamonds are forever. I'll represent 永 with a diamond ring.

世 = 廿 + L : Mnemonic symbol: the WTO or WHO.

Sherlock Holmes (sh) is cleaning a flower pot (廿) under the shower of the space station's bathroom (Ø4) with a loofah (L) because he didn't quite understand a poster next to the shower from the WHO (世) explaining dangers arising from different germs.

In this case, L is for loofah.