mechanical reel scoring and the "add-a-ball" feature for locations that didn't allow game replays. By 1967, pinball was in the middle of its so-called "golden age", and the number of pinball units that sold began to increase dramatically. Popular Williams pinballs included Shangri-La (1967), Apollo (1967), Beat Time (1967), Smart Set (1969), Gold Rush (1971), and Space Mission (1976). Golden age of arcade games Taking note of Atari's success with Pong in 1972, Williams decided to enter the fledgling coin-operated arcade video game industry. After preliminary negotiations with Magnavox, it subcontracted the Magnetic Corporation of America to create its first arcade video game Paddle-Ball. In 1974, the company was reincorporated as Williams Electronics, Inc. In 1980, Seeburg, facing bankruptcy, sold Williams to Louis Nicastro, who, with his son Neil, would take the company public and run it for over two decades. Williams developed its own breakthrough hit with the release of 1981's Defender, whose gameplay, horizontal scrolling, and dynamic color influenced many subsequent games. It was followed by a sequel in the same year, Stargate, and a group of popular and influential titles: Joust, Robotron: 2084, Sinistar, and the licensed Moon Patrol. With the exception of Sinistar, these were widely ported to home systems by external developers and publishers including Atari. After Dragon's Lair popularized LaserDisc video games in 1983, Williams created the LaserDisc/computer graphics hybrid racing game Star Rider which lost, or contributed to a loss of, $50 million for the company. In 1988, Williams acquired Bally/Midway, the consolidated amusement games subsidiary of longtime competitor Bally Manufacturing, which left the business to concentrate on casinos. Midway saw strong sales in the early 1990s with a number of successful arcade games, including Mortal Kombat and NBA Jam. Solid state pinball Williams' first solid-state machines produced in 1976 were prototype runs based on electromechanical games; Aztec (1976) and Grand Prix. Williams continued to release new electromechanical pinball machines through October 1977, when they released their last, Wild Card. From November 1977, Williams released solid-state pinball games exclusively, beginning with their first solid state production model Hot Tip (1977), which sold 4,903 units (the electromechanical version previously released in June sold 1,300 units). From the late 1970s through the 1980s, Williams released numerous innovative pinball games, such as Gorgar (1979, the first pinball featuring a synthetic voice), Firepower (1980), Black Knight (1980, the first featuring multiple levels), Jungle Lord (1981), Space Shuttle