Scarlet started with a simple rule: the colour is red, and the person doesn't have to show their face.
What happened next surprised me. Without a face to read, you start reading everything else: the angle of a neck, the pattern of a sleeve, whatever someone holds up between themselves and the camera. These are still portraits. They just let the sitter decide what goes first.
Most of us do this every day anyway. We choose what people notice about us before they get to the rest.