嵴

山 = 丨 + 凵 : Mnemonic symbol: 山 looks like the tip of a fork. Sherlock Holmes (sh) is climbing a mountain (山) in front of the anthill (an1). He uses a dinosaur bone (〡) as walking stick, and to have better grip he attached a fork (山) to its tip. Unfortunately he accidentally sticks the fork into a receptacle (凵) on the ground of the mountain and gets shocked.

脊 = 兆 + 月 : Joan of Arc (ji) collapsed on the ridge (脊) of the moon during her hike in the space station's living room (Ø3). A vulture (兆) is waiting nearby for Joan to die so it can rip out her spine (脊).