For me this is the best one.
The squares A and B in the image below are exactly the same Colour.
I couldn't actually see that even though the truth is that they are.
Here's how I proved it to my own satisfaction.
I printed the image on a A4 sheet of paper then placed a blank A4 sheet of paper over the sheet with the image. I marked the four corners of the two squares (traced them) and then cut out the two squares. I then placed the blank A4 sheet with the two cut outs over the sheet with the image and it was 100% obvious to the naked eye that both squares were without doubt exactly the same colour. It has something to do with the shadow thrown by the green cylindrical object and the brain being thrown by the fact that there are multiple squares in the image.
Give it a go when you have nothing better to do
The squares A and B in the image below are exactly the same Colour.
I couldn't actually see that even though the truth is that they are.
Here's how I proved it to my own satisfaction.
I printed the image on a A4 sheet of paper then placed a blank A4 sheet of paper over the sheet with the image. I marked the four corners of the two squares (traced them) and then cut out the two squares. I then placed the blank A4 sheet with the two cut outs over the sheet with the image and it was 100% obvious to the naked eye that both squares were without doubt exactly the same colour. It has something to do with the shadow thrown by the green cylindrical object and the brain being thrown by the fact that there are multiple squares in the image.
Give it a go when you have nothing better to do