memes

The real dress is actually blue and black, yes, but the illustration tries to show how the exact same colours can look different depending on lighting and context.

In the diagram, the dress on the left is strongly blue and black, while the dress on the right is strongly white and yellow.

And yet the connected parts of the dresses with the "pipes" between them show the exact same colour on one dress can look like a different color on the other. The "pipe" is there so you can follow it with your own eyes from one side to the other and observe that it is indeed the same colour on both sides, despite looking very different when observed as part of the whole image.

The point being, how our brains perceive colour is very situationally dependent, and some people assume a different situation than others, hence the differences in perception.

People tend to believe that vision is absolute, that we all have the same eyes and see the same things, but that's absolutely not true. The dress phenomenon occurred because It's not about what your "eyes" see in absolute terms, it's about what your "brain" does with that information.