Our brains work in complex and strange ways. There are some people who can calculate the day of the week for any given date in 40,000 years, but who cannot add two plus two. Others can perform complex classical piano pieces after hearing them once, but they cannot read or write. Dr. J. Langdon Down first described this condition in 1887. He called these people idiot savants. An idiot savant is a person who has significant mental injury, such as in autism (自闭症) or retardation. At the same time, the person also exhibits some extraordinary skills, which are unusual for most people.