紅不讓

红 = 工 + 纟 : Mnemonic symbol: a little red book.

Helga Horse (hu) is reading the little red book (红) in the engine's kitchen ((e)ng2), when she discovers that it is being eaten by a silk worm (纟). She overreacts a little and wants to beat the silk worm with a steel beam (工).

不 = 丆 + 卜 : Bruno Bear (bu) is setting up a wind wheel (丆) with a voodoo staff (卜) in the space station's bathroom (Ø4). He also puts a "forbidden" sign (mnemonic symbol for 不) on it, to make clear that it may not (不) be stopped.

让 = 上 + 讠 : Robinson Crusoe badly needs to use anglepod's bathroom, but currently it's under renovation. On the toilet seats there's a sign saying "上" and pointing to an advertising column, so Robinson thinks that they just want him to sit on top of the advertising column, and indeed there's a hole at the top of the column.