Light and colors can really twist how we perceive things. Looking at the picture, most of us with normal vision will see the block#1 is darker than the block#2.
However, they are actually the same exact shade of gray. The dividing horizontal shading and background colors just “incorrectly” accentuates one over the other.
What happens if we take that section out?
Now you at least begin to see they’re not different grays or not by much, right? I haven’t changed anything else on the picture, simply erased the horizontal band.
Now what if I removed the background as well? The difference of skyblue and green is still doing something to the eyes, I think…
Let’s remove the background and just put an outline around the blocks (only so it’s easier to repaint the background) and repaint the background to white. Nothing else is touched!
Now, the blocks are essentially of identical shade of gray:
Compare this again to the top-most image 🙂
If you think I have edited the blocks’ shades, download the images and check it yourself.