You'd be walking on the beach, as you look in the corner of your eye, you turn and look to see what it is specifically, it is a pair of feet, laying on the sand. They belong to a girl. You kept standing there, watching her toes curl up, and move, her feet get scrunched up, you just kept staring, the girl doesn't know that you're there, staring at her soles. You'd sit down, watching her soles.