You may have heard the "yanny" and "laurel" debate that divided the internet in recent days, but incredibly there's a new teaser that gives you a choice about what you're hearing.
But if you hear yanny, and you're still confused as to how on earth anyone could hear anything different, you're not alone.
"Like a radio, our brains can selectively tune into them, once we know what to listen out for".
"Acoustically ambiguous" in this case means that it's a very poor-quality file.
However, the voice clip has gone viral, with plenty of newscasters airing the clip on their programs, perpetuating the question.
"Clear as day, I hear Laurel", Ted Phaeton said.
"I first saw (the clip) was being used when it was brought to my attention by some of my followers on Twitter".
She's an audiologist with Bon Secours Saint Francis Health System and says there are many factors.
It turns out that there is a definitive answer to which word the clip is saying.
The different audio perceptions, scientists told The Times, may stem from the presence of "acoustic patters. midway between those for the two words" or from listeners' focus on different audio frequencies.
The San Antonio Humane Society has named two puppies after Thursday's "Yanny vs. Laurel" viral phenomenon.
He noticed similarities in the features of these words, which you can see below.
Also, some people are hearing something totally different (pray for them).
So why is it that some people are insistent that what they're hearing is "green needle"? That probably wouldn't happen in a high-quality recording, he says, or if it were spoken in a full sentence to give people more context clues.
Patricia Keating, a linguistics professor and the director of the phonetics lab at UCLA, said: "It depends on what part (what frequency range) of the signal you attend to". If you want to experiment, the New York Times made a simulator to resolve the Yanny vs Laurel debate, although no one has done the same yet for Green Needle vs Brainstorm. "Yanny or Laurel." More than 14,000 people responded and posted what they heard.
It plays a single word.
Ellen recalled the dress debate as well, but said she sees a gold and white dress. And if you mess with the frequencies in a recording, you can change what people hear - it's similar to the way that our eyes can be tricked by an optical illusion.
She provides another example.
Ellen's other guest, Shawn Mendes, said "I hear laurel".