These four events repeat every 'tropical' year (365 days, 5 hours, 49 minutes), so they become later by about six hours, or (if there has been an intervening leap day) earlier by about 18 hours, from one year to the next.
The three distinctive signs and symptoms of autism include problems with verbal and nonverbal communication, difficulties with social interaction, and repetitive behaviors or narrow, obsessive interests. There are three distinctive symptoms of autism.
Children with autism have difficulty letting others know what they want or need until they are taught how to communicate through speech, gestures, or other means. Repetitive Behaviors. Although children with autism usually appear physically normal, odd repetitive motions may set them apart from other children.