A cloud can look like a camel, but a camel is unlikely to look like a cloud. This is so because the signifier must be able to stand for the whole category of the signified. The cloud looks like all camels, but no camel looks like all clouds.
I'm the guy who will eat something that looks nice when I'm out, but when I take it home in a doggie bag, it'll sit in the back of my refrigerator until it starts to move.