Some saw it as black and blue, while others saw it as white and gold. Hilarity ensued, friendships ended, and the internet broke. Good times.
A team of New York University scientists think they know how to re-create the optical illusion behind that drama. But they need your help.
There's no right answer...but some are more right than others.
Now here comes the science part.
Thanks! We'll have an explanation for this effect soon — and tell you if the numbers the science team predicted match the results.