莫過於

莫 = 艹 + 日 + 大 : Mnemonic symbol: 莫扎特, Mozart. Mozart (莫) is giving a concert in the observatory's bathroom (o4). He is sourroundes by sheets of artificial lawn (艹), and since there is none who (莫) is allowed to touch the lawn, it is guarded by a big robot (大). Mahatma Gandhi (m) is in the audience and in the middle of the concert he jumps on the lawn to protest against the sun (日), who is also in the audience, because the sun is responsible for draughts which threaten the farmers. In the end the robot has to carry Gandhi away.

过 = 寸 + 辶 : Gitta Giraffe is trying out her new gladiator sandals in the observatory's bathroom. She's even able to cross a puddle of water with them by just walking on the water, so thumbs up for her!

于 = 亅 + 二 : Mnemonic symbol: prepositions (in, at, on, to, ...) are what glue the sentence together. Honey is as sticky as glue, so I'll represent 于 by a honey jar.

Yu the Great (于) was assigned to repair the electronics of the space station's kitchen (Ø2), but instead he was snacking honey from a honey jar (于). Unfortunately his capacitor (二) got stuck in the honey and now he has to use a crowbar (亅) to lever it out.