Elena and Cas
Her bright smile was contagious, and Cas began chattering away in excitement. "Yes. I like festivals. I've been to others, but not like this. I didn't have a vessel then. A woman painted my face for me, look." He turned and tilted his head to show her.
"Everything is so colorful," he sighed happily. "More colorful, I think, than everyone realizes." Here, his mind jumped, racing down a tangent. "Did you know that some species of butterfly have at least 15 different kinds of photoreceptors in their eyes? Humans only have three different kinds of cones, for color vision. Butterflies can see colors that humans have no possible way of perceiving."