素不相识

素 = 龶 + 糸 : Susan Saint Bernard (su) has decided to become a vegan (素) and to let everyone know. In the space station's bathroom (Ø4) she manufactures a fancy headdress (龶) in the form of a vegan flower (素) out of her own spider silk (糸) so that everyone who sees her instantly knows that she's vegan (素).

不 = 丆 + 卜 : Bruno Bear (bu) is setting up a wind wheel (丆) with a voodoo staff (卜) in the space station's bathroom (Ø4). He also puts a "forbidden" sign (mnemonic symbol for 不) on it, to make clear that it may not (不) be stopped.

相 = 木 + 目 : Mnemonic symbol: I take "eye" and "tree" as resembling an ent, an alive tree. Xi Shi (xi) portrays (相) an ent (相) in the anglepod's bathroom (ang4). Unfortunately she's really bad at painting, and her portrait resembles more a Christmas tree (木). The Eye of Providence (目) enters and, just from the shape of the Christmas Tree, instantly recognizes its own portrait (相).

识 = 只 + 讠 : Sherlock Holmes (sh) is inspecting the new arrival at the entrance of the space station (Ø2). It's a big advertising column (讠) with a cuttlefish (只) on it, to broaden the space station's inhabitant's knowledge (识).