代數式

代 = 亻 + 弋 : Rosa Luxemburg (亻) wants to practice her archery skills in the airplane's bathroom (ai4). On the other side Don Quixote (d) is standing, but they don't have an apple, so they substitute the apple with a token (代, 代币). Don Quixote is trembling heavily as Rosa lifts her bow (弋) and prepares to shoot down the token from Don's head.

数 = 娄 + 攵 : Sheldon Shrimp (shu) occupied a lunar mansion (娄) inside of the space station (Ø3) although he knows that it is to be torn down. Outside of his lunar mansion the construction (or rather destruction) workers are already counting (数) down from ten. When they count (数) zero, they will start taking down the whole thing with their sledgehammers (攵).

式 = 工 + 弋 : I'll use a specific style as mnemonic symbol: 哥特式, gothic.

Sherlock Holmes and the goth are celebrating a Viking festival in the space station's bathroom. They don't have trunks to throw around, so they use a steel beam. They also celebrate by practising archery. In zero gravity it is easy for them to set one world record after the next.