人人皆知

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 (㇏).

皆 = 比 + 白 : Joan of Arc (ji) wants to be known by everyone (皆). To make sure to reach her goal she wears a bikini (比) in front of the elevator (e1) and inspects herself in a hand mirror (白).

知 = 口 + 矢 : Mnemonic symbol: Francis Bacon is attributed to have stated "scientia potentia est", "knowledge is power". I'll thus represent 知 by Francis Bacon. Francis Bacon (知) and James II of England (zh) are playing darts (矢) in front of the space station (Ø1). Because they lack a dart board they just use a mandarin (口).