There's a new optical illusion taking over the internet known as the McCollough effect.
Similar to the white and gold or black and blue dress illusion that went viral a few years ago, scientists warn that staring at these images could have a much longer lasting effect.
To trigger the McCollough effect one must stare at the coloured vertical and horizontal lines for three minutes each, before looking at the black-and-white lines.
After a while the mind will be tricked into thinking that the black-and-white lines are coloured and they may appear red, green or pinkish.
A study carried out on the McCollough effect in 1975 found that some people were still seeing black-and-white as green and red up to three months after triggering the illusion.