人口密度

人 = 丿 + ㇏ : Mnemonic symbol: Neanderthal Man (人). Robinson Crusoe (r-) is looking for snacks in the encampment's kitchen (-en2) when he suddenly spots Neanderthal Man (人). Neanderthal Man offers him a banana (丿), but Robinson Crusoe doesn't trust the present and pokes it with a finger (㇏).

Mnemonic symbol: 口 shall be represented by a mandarin. Karl Marx (k-) is enjoying a mandarin in the outhouse's living room (ou3).

密 = 宀 + 必 + 山 : Marilyn Monroe (mi) is secretly (密) making out with her secretary (密) Khubilai Khan (必). Because it has to be a secret (密), they meet in the space station's bathroom (Ø4) and hide under a huge graduation cap (宀). Just to be sure Khubilai Khan has two forks (山) in his hands to attack anyone who might enter and see them.

度 = 又 + 广 + 廿 : Mnemonic symbol: a thermometer.

度 = 又 + 广 + 廿 : Doggy Dog follows a rigid training plan in the space station's bathroom to spend his time, even though he is sick and has a fever. To measure the degree of intensity of his fever, he uses a thermometer to measure his temperature. Even while doing this he still boxes a flower pot (which he suspended from a parachute) with his boxing glove.