Warning: this optical illusion may 'break your brain' for hours
Named after the American psychologist who discovered it, the McCollough Effect is the reason that white/blue dress went viral last year.
By staring at a test grid of red and green lines then staring at similar image in black and white you can trick your brain into seeing red as green and green as red – sometimes for up to two months!
Interestingly, scientists still don't fully understand the reason for the optical illusion. In the final image horizontal lines should appear pinkish and vertical lines a bit green.
Whatever you do, don't try this at home for more than 15 minutes. Things might never be the same again. At least it's one way to get out of a ticket for running a red...
Step 1: Stare at these images for five minutes, alternating between the two
Step 2: What colours do you see here?