The third-person narrator of "The Rocking-Horse Winner" uses a simile to describe the house's voice:
So Uncle Oscar signed the agreement, and Paul's mother touched the whole five thousand. Then something curious happened. The voices in the house suddenly went mad, like a chorus of frogs on a spring evening.
The last line of this quote compares the voices in the house to "a chorus of frogs on a spring evening," therefore employing a simile that makes use of auditory imagery. Anyone who has heard a large number of frogs knows that they are often overwhelmingly loud. By describing the voices of the house as being so loud, the story suggests that it's impossible to ignore the unsettling desire to constantly strive to earn more money. Even though Paul's behavior has led to an influx of money in the home, the implication is that this has only led to an even greater desire to become wealthy. This simile thus reinforces the story's commentary on the negative impact of greed. When people are unhealthily fixated on money and material gain, an increase in money will not sate their hunger—to the contrary, as seen with Hester and Paul, the volume and intensity of the "voices" only increases as the addiction to money and gambling worsens.