CRI > 100 windows
Color rendering index is defined as 100 for a blackbody radiation curve, but what if natural light isn't actually the best possible curve for distinguishing color? It could be something else, like for example, a flat envelope. What if we had windows that filter sunlight, and pass along white light of a lower intensity, but with a superior intensity curve for distinguishing color. While the overall intensity would be lower, the iris would adjust and therefore the eye could still see with better color distinction.