The Rubin Vase is a classic optical illusion that has been around since 1915. It is a two-dimensional image of a vase that can also be seen as two faces in profile looking at each other. The Rubin Vase is a great example of how our brains can interpret the same
From Wikipedia
The Rubin vase is a famous example of ambiguous or bi-stable two-dimensional forms developed around 1915 by the Danish psychologist Edgar Rubin.