朽

朽 = 丂 + 木 : Marie Curie (xi) visits the outhouse (ou3) in late summer and finds an old rotten (朽) Christmas tree (木). In fact the tree is so rotten that she can't endure the smell and has to put on a breathing mask (丂).

Mnemonic symbol: a breathing mask.

The air inside of the aorta is so bad that Karl Marx needs a breathing mask to breathe freely.

木 = 八 + 十 : Mnemonic symbol: a Christmas tree.

Malte Monkey (mu) is setting up a Christmas tree (木) in the bathroom of the space station (Ø4). He decorates the tree with eight-balls (八) and puts a holy cross (十) at the top of the tree.