I’m sure I’ve noticed it before, but this is the first time that I’m taking active note of it: the narrative technique of introducing a certain imagery as a simile and, immediately afterwards, using it as a metaphor. (Metaphor is, perhaps, not the most suitable term, but, for the moment, it will have to do.)
Consider, for instance, this passage from Frances Hardinge’s Fly by Night:
There was no escaping the sound of water. It had many voices. The clearest sounded like someone shaking glass beads in a sieve. The waterfall spray beat the leaves with a noise like paper children applauding. From the ravines rose a sound like the chuckle of granite-throated goblins.
The goblins chuckled at Mosca as she scrambled down the slicked roof of Twence the Potter’s hut. She realized that she would never hear the sound of their chuckle again, and to her surprise felt a tiny sting of regret.
Despite being one in a sequence of wonderful and striking images, “the chuckle of granite-throated goblins” is stronger for also being evoked as a metaphor, which, in turn, is doubly effective for having first been introduced as a simile.