behind the brain

Take a look at these railway  tracks which of the tow red rectangles is larger.Both of red  rectangles are actually  the same width and height  your  brain sees the  image as  realistic 3d  scene  in which things look  smaller as they  get farther away. So  your brain interprets  the fall 2d upper  rectangle   at  if  it 's  and  compare  its size against the smaller tracks which make it seem bigger than than the bottom rectangle. form called national geographic kids