(Credit: Delpixel/Shutterstock) Thanks to the architecture in our eyes, we see but a small subset of the hues that make up the visible spectrum. We only have three kinds of cones, or color-sensitive cells, to make sense of what could be millions or even hundreds of millions of colors. We still do a pretty good job of it — normal human eyes can pick out about a million different colors, far more than we have ever come up with names for. Still, we could conceivably do better. More cones would detect more combinations of colors and ever more subtle distinctions between shades. Some people, called tetrachromats, actually possess an extra cone and can see colors invisible to the rest of us. Now, for those of us not blessed with such a mutation, researchers at the University of Wisconsin-Madison have devised a pair of lenses that splits the color spectrum to turn us into artificial tetrachromats.