Games of skill had been popular amusement-park midway attractions since the 19th century, and with the introduction of solid-state electronics and coin-operated machines, presented the opportunity for a viable business. When pinball machines with electric lights and displays were introduced in 1933, but without the user-controller flippers which would not be invented until 1947, these machines were seen as games of luck, as well as amoral playthings that drew the attention of rebellious young people to them, and numerous state and city bans were placed on these machines which lasted into the 1960s and 1970s.