国界

国 = 囗 + 玉 : Mnemonic symbol: a nation's flag. Let's say the Chinese flag.

In the observatory's kitchen (o2) Gitta Giraffe (gu) is practising her ballet performance. She got a whole crate (囗) full of jade bracelets (玉) and flags (国) and fixed one flag to each jade bracelet. This makes a perfect combination for throwing the ring with the flag waving behind it and catching the ring again after a few pirouettes.

界 = 介 + 田 : Joan of Arc wants to leave this world and sets up a rocket launch field in the elevator's bathroom. The field looks like a normal crop field, except that there's a rocket in the middle and that the Joan of Arc marked the boundary with white and red tape.