The squares labelled A and B are actually the same colour. But because of what is around it, our brain fills in the gaps and goes “well now, we can’t have that thing messing up such a lovely pattern! I’ll just make it look like a white square in a shadow! c: ”
Your brain outright lies to your consciousness in order to make it look okay. If you remove the things around it, you get two squares the same colour.
Fuck I’m at a fencing tournament and literally a minute after I reblogged this my dad told me that he talked to the point people and I’m probably going to win a medal.