Blue...

Seeing this tweet set me off on this rabbit-hole...

Some of the most brilliantly blue things in nature don't have a single speck of blue pigment: http://t.co/tYTVRzui8J pic.twitter.com/owQjRwLmQQ
— NPR News (@nprnews) November 12, 2014

Let me begin by saying, "I love the color blue."