中新世

中 = 丨 + 口 : Mnemonic symbol: a dart board, because you always try to hit the center.

Julian Giant Squid (zhu-) is throwing dinosaur bones (丨) as darts on a dart board in front of the engine ((e)ng1). To make it a bit more difficult he's throwing mandarins (口) into the air as well and skewers them up right in the center (中 is a mandarin skewered on a dinosaur bone) in mid flight with the dinosaur bones. He's still able to consistently hit the center (中) of the dart board.

新 = 亲 + 斤 : Xi Shi (xi) and her bride (亲) are inspecting their wedding presents in front of the encampment ((e)n1). There's a brand new (新) pair of barbells (斤) packed in plastic foil.

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.