Synesthesia is a perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway. In grapheme-color synesthesia, individual letters of the alphabet and numbers are associated with specific colors and sometimes colorful patterns. While different individuals usually do not report the same colors for all letters and numbers, studies with large numbers of synesthetes find some commonalities across letters (e.g. A is likely to be red). A number of artists, writers, and scientists had synesthesia, among them Vincent Van Gogh, Wassily Kandinski, Vladimir Nabokov, Nicola Tesla, etc. Some synesthetes are reported to have learned how to apply their ability in daily life and work, for example, have used their abilities in memorization of names and telephone numbers, mental arithmetic, and more complex creative activities like producing visual art, music, and theater.