" The human eye has three kinds. One type excels at detecting red and associated wavelengths. One is tuned to blue. The other optimally perceives light of two colors: purple and yellow. The human eye is superbly equipped to detect these colors and send a signal pulsing to the brain. This doesn’t explain why I perceive them as beautiful, but it does explain why that combination gets my undivided attention. I asked my artist buddies about the power of purple and gold, and they sent me right to the color wheel: these two are complementary colors, as different in nature as could be. In composing a palette, putting them together makes each more vivid; just a touch of one will bring out the other. In an 1890 treatise on color perception, Goethe, who was both a scientist and a poet, wrote that “the colors diametrically opposed to each other . . . are those which reciprocally evoke each other in the eye.” Purple and yellow are a reciprocal pair. "

― Robin Wall Kimmerer , Braiding Sweetgrass: Indigenous Wisdom, Scientific Knowledge, and the Teachings of Plants