This, however, increased the curvature of the lens ... a mixture of all colors of the spectrum. When white light passes through a curved lens it breaks down into its various component colors ...

How could something so complex, they argue, have developed through ... light-sensitive spot evolved into a retina, the layer of cells and pigment at the back of the human eye. Over time a lens ...

It sometimes can occur, though, when the curvature of light is on tremendous scales ... with bright blue lines drawn through it where the spiral arms have been stretched into circles.