The Parisian presentations are in full swing and the ever-well-layered editors and bloggers loitering around fashion week (you know, nonchalantly) show no sign of fatigue. Hits of orange, red, canary yellow, and florescent pink livened up the cool gray landscape, and Yves Klein blue showed up everywhere from Katy Perry's coat (plus matching turquoise hair!) to shirts, totes, shoes, and capes. Click through our slideshow for a lesson in color theory.