(classifier used before a noun that has no specific classifier) / (bound form) individual
个
=
丨
+
人
:
Mnemonic symbol: Neanderthal Man (人). Neanderthal Man (人) needs to use the elevator's bathroom (e4) but it's occupied by Guy Fawkes (g), and there's only space for one individual (个). Impatiently Neanderthal Man knocks on the door using his dinosaur bone (丨).
within / among / in / middle / center / while (doing sth) / during / (dialect) OK / all right
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.
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 (㇏).