Top: west 西, bottom: repeat/again 復 (= to go 彳 with a reverse 复) [reverse 复 = Who first lies on a tatami mat 日 and then sits cross-legged 夂, has reversed.]
Mnemonic
(Westerly wind could be dangerous at sea?) If we repeat our westward-journey, we could capsize (... or turn-over).
The upper stroke 一 can be seen as the horizon, with variations of sun 日 and two legs 儿, which stand for a downward motion: Below the horizon sinks the sun (at sunset) in the west.
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