tree / wood / coffin / wooden / simple / numb / one of the eight categories of ancient musical instruments 八音[ba1 yin1]
木
=
八
+
十
:
Mnemonic symbol: a Christmas tree. Malte Monkey is putting up a Christmas tree (木) in the bathroom of the space station (Ø4). He's using a cross (十) as a base to put the tree on, and decorates the tree with eight-balls (八).
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).