步哨

步 = 止 + 丨 + 丶 + 丿 : Mnemonic symbol: a five-paced viper, 五步蛇.

Bruno Bear (bu) was strolling (步) around the space station's bathroom (Ø4) with a dinosaur bone (丨) as walking (步) stick in his hands. He disregarded the barrier (止) marking the wild, forbidden area lightheartedly and just jumped over it whistling a joyful tune. But shortly afterwards he made a terrible realization: only five paces (步)away there was a five-paced viper (步) hiding under a petal leaf (丶)! Bruno knew the viper was after him, so he tried to keep it at distance using his dinosaur bone and feeding it bananas (丿) while at the same time slowly backing up to the barrier.

哨 = 口 + 肖 : The little prince (肖) took a part time job working as a sentry (哨) for Sherlock Holmes (sh). In the aortas's bathroom (ao4) he whistles (哨), thereby giving the secret signal to Sherlock. Sherlock answers by holding up a mandarin (口), which is the secret signal of acknowledgement.