杞

This character looks like a butcher's hook. In the space station, Joan of Arc wants to conduct an experiment about a sixth order chaotic pendulum. First she hooks a butcher's hook to a sickle, then sticks the sickle's end into a flute, and finally hooks the handle of a shovel into the last hole of the flute. She then swings the chaotic pendulum to observe its behaviour.

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).