There phrases is a metaphor. Many things, processes, people and evens can be compared to the way a series of dominoes fall down. So metaphors about the domino theory may considered mixing a metaphor, which might be confusing a teaching device.
METAMIA is a free database of analogy and metaphor. Anyone can contribute or search. The subject matter can be anything. Science is popular, but poetry is encouraged. The goal is to integrate our fluid muses with the stark literalism of a relational database. Metamia is like a girdle for your muses, a cognitive girdle.