The apparent duck becomes an obvious rabbit
refers to a paradigm shift. I've only seen one paper including it, and the author uses it as if it is common. Is it used elsewhere, or with a different comparison?
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Limited as Google is as a tool for lexical research, the fact that Googling the phrase fails to turn up anything beyond this question suggests it's unique to the author. I don't think they've used it as though it's common, though; it's simply a reference to a relatively well-known visual paradigm shift.
At least in philosophy, the duck-rabbit illusion was first made famous by Wittgenstein in his "Philosophical Investigations": http://en.wikipedia.org/wiki/Philosophical_Investigations