Почитайте https://yandex.ru/turbo?text=https%3A%2F%2Fru.wikipedia.org%2Fwiki%2F%25D0%2592%25D0%25B8%25D0%25BD%25D0%25BE%25D0%25B4%25D0%25B5%25D0%25BB%25D0%25B8%25D0%25B5_%25D0%25B2_%25D0%259A%25D0%25B8%25D1%2582%25D0%25B0%25D0%25B5