A famous optical illusion has become the latest social media craze, with debates ensuing about the picture's true subject.
The image, which first appeared in a German magazine in 1892 but was made famous by American psychologist Joseph Jastrow in 1899, shows what appears to be either a duck or a rabbit.
The original question surrounding the image was posed anonymously in German magazine Fliegende Blatter.
"Which animals are most like each other?" the magazine asked at the time.
Though many people have debated that the animal is either one or the other, the true test behind the image, according to Jastrow's research, is whether or not a person can see both animals.
Research conducted by the psychologist suggested that people who are more creative were able to switch between rabbit and duck more quickly than others upon viewing the drawing.