The unusual behaviors and interests of autistic children—lining up toys, staring at ceiling fans, twirling, flapping hands repeatedly, fascination with knobs, buttons, switches, letters, shapes and digits, watching the same video again and again, singing the same song over and over—these activities betray a form of perception completely unlike that of most other children, a perception noticeably absent in social and biological focus, but also noticeably drawn to symmetry, repetition and pattern.